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Full Frame, Log Video, Micro 4:3, Panasonic GH5, Tips, UNDERWATER VIDEO

The truth about v-log

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There is no doubt that LOG formats in digital cameras have a halo of mystery around them mostly due to the lack of technical documentation on how they really work. In this short article I will explain how the Panasonic V-Log actually works on different cameras. Some of what you will read may be a surprise to you so I have provided the testing methods and the evidence so you can understand if LOG is something worth considering for you or not. I will aim at making this write up self-contained so you have all the information you need here without having to go and search elsewhere, it is not entirely possible to create a layman version of what is after all a technical subject.

Panasonic V-LOG/V-Gamut

A logarithmic operator is a non-linear function that processes the input signal and maps it to a different output value according to a formula. This is well documented in Panasonic V-Log/V-Gamut technical specifications. If you consider the input reflection (in) you can see how the output is related to the input using two formulas:

  1. IRE = 5.6*in+0.125 (in < cut1 ) *
  2. IRE = c*log10(in+b)+d (in >= cut1 ) 

Where cut1 = 0.01, b=0.00873, c=0.241514, d=0.598206

There are few implications of this formula that are important:

  • 0 input reflectance is mapped to 7.3% IRE
  • Dark values are not compressed until IRE=18%
  • Middle Grey (18% reflectance) is still 42% IRE as standard Rec709
  • White (90% reflectance) is 61% IRE so much lower than Rec709
  • 100% IRE needs input reflectance 4609 which is 5.5 stops headroom for overexposure.

So what we have here is a shift of the black level from 0% to 7.3% and a compression of all tones over 18% this gives the washout look to V-LOG that is mistakenly interpreted as flat but it is not flat at all. In fact the master pedestal as it is known in video or black level is shifted. Another consequence of this formula is that VLOG under 18% IRE works exactly like standard gamma corrected Rec709 so it should have exactly the same performance in the darks with a range between 7.3% and 18% instead of 0-18%.

In terms of ISO measured at 18% reflectante V-LOG should have identical ISO value to any other photo style in your camera this means at given aperture and exposure time the ISO in a standard mode must match V-LOG.

When we look at the reality of V-LOG we can see that Panasonic sets 0 at a value of 50% IRE so generally ⅔ to 1 full stop overexposed this becomes obvious when you look at the waveform. As a result blacks are actually at 10% IRE and whites at 80% once a conversion LUT is applied.

Challenges of Log implementation

LOG conversion is an excellent method to compress a high dynamic range into a smaller bit depth format. The claim is that you can pack the full sensor dynamic range into 10 bits video. Panasonic made this claim for the GH5s and for the S1H, S5.

There is however a fundamental issue. In a consumer digital camera the sensor is already equipped with a digital to analog converter on board and this operates in a linear non log mode. This means the sensor dynamic range is limited to the bit depth of the analog to digital converter and in most cases sensors do not even saturate the on board ADC. It is true that ADC can also resolve portions of bits however this does not largely change the picture.

If we look at the sensor used in the S1H, S5 this is based on a Sony IMX410 that has saturation value of 15105 bits or 13.88 stops of dynamic range. The sensor of the GH5s which is a variant of Sony IMX299 has a saturation of 3895 (at 12 bits) or 11.93 stops.

None of the S1H, S5 or GH5s actually reaches the nominal dynamic range that the ADC can provide at sensor level. The sensor used by the GH5 has more than 12 stops dynamic range and achieves 12.3 EV of engineering DR, as the camera has 12 bits ADC it will resolve an inferior number of tones.

So the starting point is 12 or 14 stops of data to be digitally and not analogically compressed into 10 bits coding. Rec709 has a contrast ratio requirement of 1000:1 which is less than 10 stops dynamic range. This has not to be confused with bit depth. With 8 bits depth you can manage 10 stops using gamma compression. If you finish your work in Rec709 the dynamic range will never exceed log2(1000)=9.97 stops. So when you read that rec709 only has 6.5 stops of DR or similar it is flawed as gamma compression squeezes the dynamic range into a smaller bit depth.

When we look at a sensor with almost 14 stops of dynamic range the standard rec709 gamma compression is insufficient to preserve the full dynamic range as it is by default limited to 10 stops. It follows that logically LOG is better suited to larger sensors and this is where it is widely used by all cinema camera manufacturers.

In practical terms the actual photographic dynamic range (this is defined as the dynamic range you would see on a print of 10″ on the long side at arm length), the one you can see with your eyes in an image, is less than the engineering value. The Panasonic S5 in recent tests showed around 11.5 stops while the GH5S is around 10 and the GH5 9.5 stops of dynamic range. Clearly when you look at a step chart the tool will show more than this value but practically you will not see more DR in real terms.

This means that it is possible that a standard gamma encoded video in 10 bits can be adequate in most situations and nothing more is required. There is also a further issue with noise that the log compression and decompression produces. As any conversion that is not lossless the amount of noise increases: this is especially apparent in the shadows. In a recent test performed with a S5 in low light and measured using neat-video assessment V-Log was one of the worst performed in terms of SNR. The test involved shooting a color checker at 67 lux of ambient illumination and reading noise level on the 4 shadows and darks chips. Though this test was carried out at default setting it has to be noted that even increasing the noise reduction in V-LOG does not eliminate the noise in the shadow as this depends on how V-LOG is implemented.

V-LOG Noisy Shadows

The actual V-Log implementation

How does V-LOG really work? From my analysis I have found that V-Log is not implemented equally across cameras, this is for sure a dependency on the sensor performance and construction.  I do not know how a Varicam camera is built but in order to perform the V-Log as described in the document you need a log converter before the signal is converted to digital. In a digital camera the sensor already has an on board ADC (analog to digital converter) and therefore the output is always linear on a bit scale of 12 or 14 bits. This is a fundamental difference and means that the math as illustrated by Panasonic in the V-LOG/V-Gamut documentation cannot actually be implemented in a consumer digital camera that does not have a separate analog log compressor.

I have taken a test shot in V-LOG as well as other standard Photo Styles with my Lumix S5 those are the RAW previews. V-LOG is exactly 2 2/3 stops underexposed on a linear scale all other parameters are identical.

Image on a standard photo mode looks correctly exposed
RAW image shot in V-LOG shows 2 2/3 underexposure

What is happening here? As we have seen ISO values have to be the same between photo styles and refer to 18% middle grey however if you apply a log conversion to a digital signal this results in a very bright image. I do some wide field astrophotography and I use a tool called Siril to extract information from very dark images this helps visualise the effect of a log compression.

The first screenshot is the RAW file as recorded a very dark black and white image as those tools process separately RGB.

Original image in linear representation

The second image shows the same RAW image with a logarithmic operator applied; this gives a very bright image.

Same image in logarithmic scale

Now if you have to keep the same middle grey value exposure has to match that linear image so what Panasonic does is to change the mapping of ISO to gain. Gain is the amplification on the sensor chip and has values typically up to 24-30 dB or 8 to 10 stops. While in a linear image the ISO would be defined as 100 at zero gain (I am simplifying here as actually even at 100 there will be some gain) in a log image zero gain corresponds to a different ISO value. So the mapping of ISO to gain is changed. When you read that the native ISO is 100 in normal mode and 640 in V-LOG this means that for the same gain of 0 dB a standard image looks like ISO 100 and a V-LOG image looks like ISO 640, this is because V-LOG needs less gain to achieve the same exposure as the log operator brightens the image. In practical terms the raw linear data of V-LOG at 640 is identical to an image taken at 100.

This is the reason why when a videographer takes occasional raw photos and leaves the camera in V-LOG the images are underexposed.

The benefit of the LOG implementation is that thanks to log data compression you can store the complete sensor information in a lower bit depth in our case this means going from 14 to 10 bits. 

There are however some drawbacks due to the fact that at linear level the image was ‘underexposed‘, I put the terms in italic as exposure only depends on time and aperture of the lens, so in effect is lack of gain for which there is no term.

The first issue is noise in the shadows as those on a linear scale are compacted, as the image is underexposed: a higher amount of noise is present and this is then amplified by the LOG conversion. It is not the case that LOG does not have noise reduction, in fact standard noise reduction expects a linear signal gamma corrected and therefore could not work properly (try setting a high value in V-LOG on a S camera to see the results), the issue is with the underexposure (lack of gain) of the linear signal.

There are also additional side effects due to what is called black level range, I recommend reading on photonstophotos a great website maintained by Bill Claff. When you look at black levels you see that cameras do not really have pure black but have a range. This range results in errors at the lower scale of the exposure; the visible effect is colour bleeding (typically blue) in the shadows when there is underexposure. As V-LOG underexposed in linear terms you will have issues of colour bleeding in the shadows: those have been experienced by several users so far with no explanation.

The other side effect is that the LUT to decompress V-LOG remains in a 10 bit color space which was insufficient to store the complete dynamic range data and this does not change. So the LUT does not fully reverse the log compression in Panasonic case this goes into the V709 CineLike Gamma which is in a Rec709 gamma. As the full signal is not decompressed means that there are likely errors of hue accuracy so V-LOG does not have a better ability to reproduce accurate colors and luminance and this is the reason why even after a LUT is applied it needs to be graded. If you instead decompress V-LOG in a log space like Rec2020 HDR you will see that it does not look washed out at all and colors are much more vibrant as the receiving space has in excess of 20 stops.

Some users overexpose their footage saying they are doing ETTR. Due to the way log is implemented this means it will reach a clipping point sooner and therefore the dynamic range is no longer preserved. This is a possible remedy to reduce the amount of noise in low light however the log compression is not fully reversed by the LUT that is expecting middle grey exposure and therefore color and luminance accuracy errors are guaranteed. If you find yourself regularly overexposing V-LOG you should consider not using it at all.

Shadow Improvement and input referred noise

The Lumix cameras with dula gain sensor have a different behaviour to those without. This is visible in the following two graphs again from Bill Claff excellent website. 

The first is the shadow improvement by ISO here you can see that while the GH5/G9 stay flat and are essentially ISO invariant, the GH5S and S5 that have a dual gain circuit have an improvement step when they go from low to high gain. What changes here is due to the way the sensors of the GH5s and S5 are constructed, the back illumination means that when the high gain circuit is active there is a material improvement in the shadows and the camera may even have a lower read noise at this ISO (gain) point than it had before because of this.

Another benefit of dual gain implementation is easier to understand when you look at input referred noise graphs. You can see that as the sensor enters the dual gain zone the input referred noise drops. Input referred noise means the noise that you would need to feed as an input to your circuit to produce the same noise as output. So this means when that step is passed the image will look less noisy. Again you can see that while the GH5 stays relatively flat the GH5s and S5 have a step improvement. Is it is not totally clear what happens in the intermediate zone for the GH5s possibly intermediate digital gain or more noise reduction is applied.

The combination of a certain type of sensor construction and dual conversion gain can be quite useful to improve shadows performance.

Do not confuse dual gain benefit with DR preservation, while dual gain reduces read noise it does not change the fact that the highlights will clip as gain is raised. So the effective PDR reduces in any case and is not preserved. The engineering DR is preserved but that is only useful to a machine and not to our eyes.

Now we are going to look at specific implementation of V-LOG in various camera models.

Front Illuminated 12 bits Sensors

Those are traditional digital cameras for photos and include the GH5, G9 for example. On those cameras you will see that the V-Log exposure shows a higher ISO value of 1 stop compared to other photo styles at identical aperture and shutter speed setting but the actual result is the same in a raw file so your RAW at 400 in VLOG is the same of another photo style at 200. This is a direct contradiction of Panasonic own V-Log model as the meter should read the same in all photo styles so something is going on here. As there is no underexposure it follows that there is no real log compression either. Those cameras are designed in a traditional way so low ISO (gain) is good high ISO (gain) is not. This is visible in the previous graphs.

Those screenshot show how the raw data of an image taken at ISO 250 in standard mode is identical to the V-LOG image and therefore shows how there is not LOG compression at all in the GH5. V-LOGL of the GH5 is therefore just a look and does not have any increase of dynamic range compared to other photo styles.

Image in standard photo style at ISO 250
Identical image at ISO 500 showing that there is no compression at all
VLOG L look of the same raw data

Is this version of V-LOGL more effective than other photo style with a compressed gamma like CineLikeD? According to Panasonic data CineLikeD has 450% headroom so it is already capable of storing the whole dynamic range that the GH5 can produce (450% means 12.13 stops vs 12.3 theoretical maximum).

In addition noise performance of V-Log is worse because all is doing is acting on shadows and highlights and not really doing any log conversion. The business case for acquiring a V-Log key on those cameras is limited if the objective was to preserve dynamic range as the camera already has this ability with photo styles included with the camera and moreover the V-LOG is not actually anything related to LOG compression otherwise the image would have needed to have less gain and would have shown underexposed. The fact that the camera is shooting at nominal ISO 400 means most likely that some form of noise reduction is active to counter the issue that V-Log itself introduces of noise in the shadows. So in this type of camera V-LOG is only a look and does not accomplish any dynamic range compression.

Back Illuminated 12 bits readout sensors

The cameras that have this technology are the GH5s and the BGH1, the back illumination gives the sensor a better ability to convert light into signal when illumination levels are low. Those cameras have actually a sensor with an 14 bits ADC but this is not used for video.

In order to decompose the procedure I have asked a friend to provide some RAW and Jpeg images in Vlog and normal. You can see that in the GH5s there is 1 stop underexposure and therefore a light form of log compression.

Standard Photo Style GH5s
V-LOG -1 stops from standard at identical setting due to gain reduction
VLOGL in the GH5s as presented by the camera

In the GH5s implementation the camera meters zero at the same aperture shutter and ISO in LOG and other photo styles and zero is 50% IRE so actually is 1 stop overexposed.

The procedure for V-Log in this cameras is as follows:

  1. Meter the scene on middle grey + 1 stop (50%)
  2. Reduce gain of the image 1 stop behind the scenes (so your 800 is 400 and 5000 is 2500)
  3. Digital log compression and manipulation

As the underexposure is mild this means the log compression is also mild as it is only recovering 1 stop as the two effect cancels this is actually a balanced setting.

The IMX299 dual gain implementation was a bit messed up in the GH5s but has been corrected in the BGH1 with the values of 160 and 800. It is unclear what is happening to the GH5s and why Panasonic declared 400 and 2500 as the dual gain values as those do not correspond to sensor behaviour, perhaps additional on sensor noise reduction only starts at those values or just wanting to make a marketing statement.

Back Illuminated 14bits Sensors

Here we have the S1H and S5 that have identical sensors and dual gain structure. 

The metering behaviour on the S series is the same as the GH5s so all photo styles result in identical metering. The examples were at the beginning of this post so I am not going to repeat them here.

Now the gain reduction is 2 and ⅔ stops which is significant. After this is applied a strong log compression is performed. This means that when you have ISO 640 on the screen the camera is actually at gain equivalent to ISO 100 and when you have 5000 is at 640 resulting in very dark images. In the case of the S5/S1H VLOG does offer additional dynamic range not achievable with other photo styles.

Interestingly V-Log on the S series does achieve decent low light SNR despite the strong negative gain bias. Here we can see that the Log implementation can be effective however other photo styles that do not reduce gain may be a better choice in low light as gain lifts the signal and improves SNR. It is also important to note that the additional DR of VLOG compared to other photo styles is in the highlights so it only shows on scenes with bright areas together with deep darks this was noted on dpreview and other websites.

Should you use V-LOG?

It looks like Panasonic is tweaking the procedure for each sensor  or even camera as they go along. The behind the scenes gain reduction is really surprising however it is logical considering the effect of a log compression. 

Now we can also see why Panasonic calls the GH5s implementation V-LOGL as the level of log compression is small only 1 stops as opposed to VLOG in the S series where the compression is 2 ⅔ stops. We have also seen that V-LOG, at least in a digital consumer camera with sensor with integrated ADC, has potentially several drawbacks and those are due to the way a camera functions.

Looking at benefits in terms of dynamic range preservation:

  1. GH5/G9 and front illuminated sensor: None
  2. GH5s/BGH1 back illuminated MFT: 1 stop
  3. S5/S1H full frame: 2 ⅔ stops

What we need to consider is that changing the gamma curve can also store additional dynamic range in a standard video container. Dpreview is the only website that has compared the various modes when they reviewed the Panasonic S1H.

A particularly interesting comparison is with the CineLikeD photo style that according to Panasonic can store higher dynamic range and is also not affected by the issues of V-LOG in the shadows or by color accuracy problems due to log compression. The measures of dpreview show that:

  1. On the GH5s V-LOG has 0.3 stops benefits over CineLikeD
  2. On the S1H V-LOG has a benefit of 0.7 stops over CineLikeD2

Considering the potential issues of noise and color bleeding in the shadows together with hue accuracy errors due to the approximation of the V-LOG implementation I personally have decided not to use V-LOG at all for standard dynamic range but to use it for HDR footage only as the decompression of V-LOG seems to have limited to no side effects. In normal non HDR situations I have shot several clips with V-LOG but I never felt I could not control the scene to manage with other photo styles and the extra effort for a maximum benefit of 0.7 Ev is not worth my time nor the investment in noise reduction software or the extra grading effort required. As HDR is not very popular I have recently stopped using V-LOG altogether due to lack of support of HDR in browsers for online viewing.

Obviously this is a personal consideration and not a recommendation however I hope this post helps you making the right choices depending on what you shoot.

This write up is based on my analysis on Panasonic V-LOG and does not necessarily mean the implementation of other camera manufacturers is identical however the challenges in a digital camera are similar and I expect the solutions to be similar too.

Micro 4:3

Olympus Divestment Next Steps and Reflections

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On September 30th 2020 the announced deal between Olympus corporation and Japanese Industrial Partners has been signed. Despite all sort of hysteria that is out there on the internet the deal structure is quite simple and there is good information released by Olympus Global on this link.

The Birth of OM Digital Solutions Corporation

The data provided tells us that the current head of the camera business will transfer to the new company that will be headquartered in Tokyo. OM stands for Olympus Maitani however the word Olympus does not feature in clear in the company name perhaps because Olympus corporation did not want to have any ambiguity or misunderstanding going forward on who is Olympus.

So the first indication is that Olympus as camera brand effectively ends when the deal completes on 31st December 2020. What continues is the legacy of Yoshihisa Maitani who originally invented the OM system.

What is included in the deal

This is the official text in the news release.

The agreement applies to Olympus’ global Imaging business, which includes all R&D and manufacturing facilities currently dedicated to its Imaging business. The New Imaging Company will continue to provide high-quality, highly reliable products. Built on a solid foundation, including the Zuiko and OM brands, which are grounded in optics and digital imaging technologies cultivated by Olympus over many years, the New Imaging Company will be appropriately positioned to further pursue new developments. Head of sales and marketing, R&D and designing departments for imaging products will be relocated to the headquarters of the New Imaging Company in Hachioji, Tokyo. Production will continue at the location in Dong Nai province, Vietnam, where imaging products are currently manufactured. The New Imaging Company will continue to provide customer support for the imaging products which have been manufactured and sold by Olympus. Following the transfer of the Imaging business, Olympus will concentrate on Medical and Scientific Solutions, in our ongoing efforts toward making people’s lives healthier, safer and more fulfilling.

So what does this mean? Today Olympus operates as a single company and the imaging business is included in it so they needed to work out what exactly they were selling. From that list this includes:
• The Zuiko and OM (Olympus Maitani) brands
• The R&D department
• The Sales and Marketing Department
• The factory in Vietnam
And Olympus will focus on the medical and scientific business. The new OMD company will take on the after sales responsibility and warranty usually associated with provisions for repairs and returns.

What is NOT included in the deal

What is not included in the transfer is usually anything not specifically mentioned as included so a few considerations here expressing my view on the deal.

The factory in Nagano, Japan is not transferring but according to JIP news release will become a supplier to the new company. This is good for JIP as the factory in Vietnam is less than 3 years old and is in a market where workforce arrangements are more flexible than Japan. The Japanese factory that makes some components for Vietnam and in some cases full lenses will remain as supplier. Olympus also uses Sigma designs for some lenses like the 75mm 1:1.8 and the new 100-400mm 5-6.3 this will continue with OMD.

The Olympus Supply Chain is currently shared with the medical division there are a number of regional and local warehouse that will remain with Olympus together with any stock that is in there. All stock at customers (distributors or resellers) remains the property of those third parties. This is an important implication because it effectively means that OMD starts at zero stock and all the inventory sitting in those warehouses are Olympus corporation problem to clear, we have already seen aggressive promotions on OMD EM1MKII with a free 1.2 Pro prime lens. I bought one of those units and it was manufactured in February 2019 so clearly Olympus corporation distribution network is sitting on years of old stock.

The Olympus commercial network also remains with the seller and this means those entities will continue to trade in the respective markets until such time OMD decides to build their network, they may even decide to use distributors and focus on manufacturing and continue to use Olympus corporation or anyone else as they see fit, what is clear is that OMD is a manufacturing company not distribution. It will remain to be seen how the after sales services will be performed however this could simply mean customers get a replacement product or goods are sent all the way back to Vietnam for fixing or they establish 3rd party service centre to deal with this issue. Panasonic currently does that.

Future Direction of OMD

JIP has mentioned that they will focus more on video and on business customers this is good news as MFT strength really is in those two sectors. Panasonic has exploited that success while Olympus was only sticking to photos and suffering more the smartphone competition. We have seen an announcement that the newer OMD EM1 MKIII E1X will work in ProRes RAW with the Atomos Ninja a first step to get in that territory. Security is a big topic in MFT too as the back illuminated sensor in the GH5s is excellent in low light.
Will JIP review the product range? For sure any situation like this sees a range rationalisation exercise. This means some SKU may be discontinued and some products in future roadmap never go to market. Olympus America website quickly put up a Q&A to that regards the three key answers are here, on the left what it says on the right what I think it means as the writing is not as black and white as you probably would like.

QuestionOfficial AnswerMy Interpretation
Will the Olympus brand name continue to be used?While our official company name will be OM Digital Solutions, you can expect the Olympus brand name to stick around for the foreseeable future. Olympus branded products will continue to be available even after January 1, 2021.The brands that will transfer are OMD and Zuiko. Olympus supply chain is sitting on a lot of old stock and currently all products being made are still branded Olympus, this will continue like that until the transaction closes. The Olympus  brand will continue to be used also because the medical company continues.
This does not mean that the cameras produced under JIP ownership will be branded Olympus and there are strong indications they will be called OMD as the word Olympus is associated with the medical company in the deal information and is not part of the new company name.

Will the new lenses announced as under development for sales in 2020 still be introduced?
There are no plans to change our product launch plans within 2020. Products that have been announced as under development will be introduced to the market as planned. You can find the most up to date information on product launches by visiting: http://www.getolympus.com
Olympus can only guaranteed what happens when they own the camera business. All things planned for Winter 2020 are going to happen if they happen before 31/12/2020 afterwards they do not know.

What is the future of Micro Four Thirds? Is there any change to the proposed lens roadmap? Will there be a future replacement for my Olympus product?		We are not able to comment on future product development at this time. For the most up to date information on Olympus products in the Americas, please visit: http://www.getolympus.comThe lens roadmap is an Olympus document what JIP will do with it is not something they know. In fact it is very likely to change if those projects are not going to provide a solid business case. They can also not comment on future cameras nor Micro-Four-Thirds are that is no longer their business

Also to be noted Micro-Four-Thirds is an open standard the fact that Olympus runs the four-thirds website does not mean anybody has to pay Olympus to make an MFT camera. So there is no issue of licensing rights connected to the MFT standard which only relates to AF and AE this is the reason you see many manual lenses not following the standard or not being listed.

Conclusion


The divestment of Olympus Imaging business is a sad moment for most as it marks officially the end of a legacy for what concerns Olympus corporation. With the performance that the business has had in the last years this was not avoidable. The new ownership will start with a streamlined business, a focus on manufacturing and a clean slate with no debts or old inventory to clear. OMD will also start with some good assets the IBIS and Auto Focus developed by Olympus are very effective and can play well especially if the new focus is on video. New more dynamic businesses like BlackMagic Design and Zcam are having success with the MFT format for video and this is an opportunity that Olympus missed entirely and hopefully the new company will grab. Will this be enough to save the MFT format from extinction? Definitely video is a more profitable segment where there are no smartphones that can really compete for those who want to be really doing a good job because the devices heat up, run out of battery and finally the editing process is still too complex that requires a workstation. I hope the OMD business can fully realise the full potential of MFT and provide a truly hybrid system, something Olympus failed to deliver with their still focussed product line. In the short term, and by this I mean the next two years, not much will change to the user experience, but we need to understand if Micro-Four-Thirds will have enough traction to continue for photography with new models or it becomes a video specialist segment.

Micro 4:3, Underwater Photography, UNDERWATER VIDEO

Olympus vs Panasonic for Underwater Use

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I have been shooting MFT underwater since 2014 coming from compacts but I have also owned DSLR cameras for land use. As I initially focussed my underwater imaging on video I adopted Panasonic MFT cameras as they have an edge in terms of video use coming from Panasonic long established video and broadcast legacy.

Recently, just days before the divestiture announcement, I have purchased an Olympus OMD EM1MKII. I have decided on this camera as during lockdown I have been attempting pictures of birds in flight and the autofocus of my Panasonic G9, that I was using since February for land pictures, was not satisfactory.

I have since pondered if it made sense to switch to Olympus also for underwater use and I have considered the pro and cons of this choice compared to Panasonic semi pro models GH5 and G9. I thought of sharing my thinking with you so that if you are considering an MFT system as your next investment for underwater imaging you have a point of reference.

Note: I am only considering the top range Olympus cameras as others do not offer in my opinion any benefit over Panasonic range.

Strengths of OMD System

Olympus OMD Auto Focus system

At time of writing the OMD EM1 series and the EM5 Mark III use an Olympus specific on sensor phase difference detection auto focus system. Note this is different to DSLR phase detection and more similar to Sony hybrid AF system.

I found this system to be very effective with birds in flight once locked on the subject and much faster in locking on subjects as long as the background was clear; with this I mean this system still struggles if there is a busy background to acquire focus. In particular the CAF with tracking is very effective for birds that do not move too fast in the air or are about to take off from a fixed spot. It also effectively tracks at higher frame rate any type of object in motion. This system is superior to Panasonic CAF that is based on motion estimation for shots following the first one of the burst. More specifically it is harder to acquire focus for the first time with Panasonic and the following shots are estimated using a motion prediction algorithm without  continuous autofocus. This feature is the one that sets Olympus camera that have phase detection AF apart from Panasonic and from more economic Olympus model such as the OMD EM10 series. Another useful feature is that in review mode it tells you what the camera focussed on.

Example Birds in Flight Shot OMD EM1MKII
This shot is taken on a Panasonic G9 using the Pre-Burst functionality

Other features of OMD system for land use

If you shoot at night another very useful feature is live composition, this is very useful for fireworks or star trails but not effective for real astrophotography for which you need a star tracker or use stacking. Other features that are present in the newer EM1MKIII like starry AF are in my opinion not useful if you know how to focus on stars.

Milky Way with Panasonic GH5 shows no tangible difference to OMD Shots

Olympus Housing Costs

As Olympus bodies are smaller and simpler the housing cost compared to Panasonic G and GH series is 30% lower this is material in the scheme of things as Panasonic Pro housing are almost as expensive as an APSC DSLR. This for me is the single most important factor.

OMD EM1MKII €1,856 list price Weight 1.95kg Dimensions 305mm (W) × 175mm (H) × 116mm (D)

Drawbacks of Olympus Cameras

Lack of on Screen Manual Focus Guide

The most evident one for macro shooters is the lack of on screen MF guide as displayed in Panasonic cameras. This very useful for macro but also for astrophotography and video as you know if your camera is at the macro or tele end. For macro underwater photography this means you know if you have hit the minimum working distance and maximum magnification so now you can focus on getting the shot using peaking. 

Olympus does not offer a guide but you can pre-set a mode called Pre-MF to minimum distance however I found the on screen peaking to be really poor and ultimately getting less magnification in macro shots.

AARGH!
Typical Macro Shots where the MF Guide feature is useful to ensure maximum subject size

Exposure Aids

While Panasonic offers customisable Zebra on screen Olympus only offers a red and blue colouring and the levels only offer limited customisation on a 0-255 8 bits scale. This is OK for checking clipping in absolute but not good for specific exposure targets.

Video Mode

The video modes of the OMD are simply poor and the codec quality just good for your occasional video. The lack of exposure aid and support for manual focus make the whole video experience very very dissatisfactory.

Framing

With Panasonic you can set framing guides on the screen for 1:1 5:4 whatever you like without changing the image aspect ratio, this is useful if you want to frame a shot for a specific platform. Olympus lacks this feature entirely.

Image Quality

I can confirm that for underwater and land use I see zero difference in performance between my OMD EM1MKII and the GH5 in the range ISO 200-1600. It is true that the Jpeg settings are different and the color rendering is different for Jpeg however shooing RAW files this becomes irrelevant and I can’t distinguish the shots when the calibrated adobe profiles are used in Lightroom. I believe at some point that Olympus images were sharper however this was due to the images being better in focus when it comes to birds and subjects fast moving.

In terms of JPEG rendering Olympus choices are better for nature and landscapes with more saturated colours, for portraits I prefer the Panasonic rendering. Again those settings are not relevant for RAW files.

Nauticam GH5V a whopping €2,862 due to the M21 Valve weights 2.36 Kg

Conclusion

In my opinion the most attractive feature of Olympus cameras for underwater photography use is actually the reduced cost and size of the housing. While the extra strength are surely worth for land wildlife photography I truly do not think they make any difference underwater. For sure it would be better to do a field test, this so far has not been possible and if anybody gives me an OMD EM1MKII housing to test I would be very happy, however using the tools made available by Panasonic I do not get almost any shots out of focus and those there are blurred are because I forgot to change a setting on the camera.

For video I cannot recommend the Olympus system at all, Panasonic is way ahead on this on a number of accounts. 

In conclusion if you are 100% focus on photography and just take an occasional video the OMD system is light more compact and less expensive. It will not give any edge to your images as the sensors are identical. If you shoot a mix of video and photos the choice is Panasonic. Rest assured none of the AF strength of Olympus will improve your hit rate, if your shots are blurred you are likely using the wrong settings with your camera. The housing costs tho are higher and the rigs are less portable.

MFT Lenses, Micro 4:3

What Happens After the Olympus has fallen?

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On June 24 2020 Olympus corporation has announced they will divest the imaging business and sell the business to be carved-out to JIP (Japanese Industrial Partners).

The full script is here: Memorandum.

Olympus had already delayed the disclosure of financial results for the year ended 31 March 2020, Nikon had already done the same. Clearly companies need to build some accounting provisions for Covid-19 however you would argue that for the year ended on 31st of March the impact of Covid-19 was not substantial as most countries only entered lockdown in March and this is not a prime period for camera sales anyway.

As as an M&A consultant specialising in carve-outs and divestment I have my views on how this will turn out based on my experience but this is not the purpose of this post. What I wanted to do is to perform a short analysis of what I think has gone wrong and what is likely to be the most significant challenge to the newco that will be formed from Olympus imaging business.

The overall situation of the camera market

According to CIPA worldwide sales in units have fallen 87% since 2010.

The overall number of images is actually growing however as of 2017 85% of those pictures are taken on mobile phones.

According to DxOMark and other sources, mobile phones are closing the gap on cameras on a number of aspects. Mobile phones have a lot of development behind and have powerful processors that combined with multiple lenses can produce stunning images.

Most images are consumed on mobile phones and are usually limited to resolutions lower than 4 megapixels or even 1.5 megapixels like Instagram we can understand where this is all going. There is software that allows you to retouch your images directly on your phones one of the reason why instagram is so popular.

As the market for digital camera shrinks camera manufacturers feel the squeeze and this means business will disappear in the process with Covid-19 putting a final stake in what was already a walking dead: Olympus camera business.

Why Olympus?

First of all Olympus is not the first company going through this, it has already happened to Pentax though this entity was sold at profit in the golden years of digital cameras. Contrary to what most people think Olympus was not originally a camera brand but started out with medical and microscopes in 1919 only in the mid 30s Olympus started making cameras and as of today Olympus is predominantly a B2B enterprise. Olympus has also been at the centre of significant corporate fraud in 2011 and in 2016 was also in the middle of a bribery scandal in US. The last ten years of Olympus corporation history have been plagued by misconduct and therefore nobody would go anywhere near a possible acquisition of Olympus assets at least until now.

As of FY 2020 the imaging division has posted 3 consecutive years of losses with a 10% revenue reduction on FY 2019. Olympus had started the restructuring of their manufacturing operations in 2017 and has cut c45% of their operating losses as result. As a division is still loosing cash and therefore if you had to evaluate the business in terms of EBIT multiplier, a common method for corporate transactions, Olympus Imaging Division is worth nothing and actually it has negative value means it costs cash just to run.

The improvement trajectory and the nature of the distressed business has fallen in the interest of JIP who specialised in acquiring divisions of loss making companies and had already closed deals with Sony, Nec to name a few.

Some Olympus consumers have felt betrayed by this move as Olympus had repeatedly affirmed they were continuing the camera business however the reality is that nobody was likely to go anywhere near it until now and the moment they have a prospective buyers this would most likely proceed as it has happened. From corporate point of view, despite the various scandals, Olympus has been increasing their operating profits as the other divisions are all successful. Removing a loss making divisions will greatly benefit the shareholders and investors and will also allow Olympus to focus on the segments that are successful. If the proposed transaction completes Olympus will effectively exit consumer markets.

So in short Olympus is divesting the imaging division because is loss making, it dilutes shareholder value and they now have a potential buyer, it would be crazy for them not to proceed in consideration of the overall situation of the camera market.

Questionable Choices

In addition to the compression of the digital camera market, Olympus has also made some questionable choices, and is affected by the overall stagnation of imaging sensors. Olympus does not make their sensors since a long time, previously they bought them from Panasonic, then lately from Sony.

Sony who makes sensors for most brands including Nikon and Panasonic, has not released anything new in the micro four thirds segment since 2017. For this reason we have not seen a rush from Panasonic to release new models and things have been pretty quiet on their front since the G9 camera in 2018 with the rest of the range just aligning to the 20 megapixel sensor.

Olympus instead has released a few models of their flagship OMD range, the EM1X and the EM-1 Mark III, both based on the same sensor technology of the previous OMD EM-1 Mark II released December 2016.

The EM1X specifically aimed at the professional wildlife photographer has a RRP of £2,699, that is the same price of a Nikon D850.

Size by Side courtesy of Camerasize.com

Combined with the Olympus 300mm f/4 prime the EM1X is 2.3 Kg while the D850 with the Nikkor 500mm f/5.6 prime is 2.4 Kg. The Nikon set up ends up being around £6K while the Olympus is £4.7K at RRP. I am not sure this is an appealing proposition considering the significant IQ difference between the two cameras and the pretty identical weight.

Also to consider that at £1,499 you can buy a Nikon D500 that has the same RRP of the new OMD EM-1 MKIII. Now it is possible that Nikon is heavily discounting items and they are going to go bust next, however you can clearly see that competing with those boys may not be a good idea.

The Micro Four Thirds Benefits

The benefits of MFT are listed in the four thirds website here.

There were 3 key items:

  1. Radical reduction in thickness, size and weight
  2. An interchangeable lens system designed to handle video in the future
  3. Continued use of four thirds lenses

Looking at the reduction in size the EM1X is not a good example for this and we can argue the Panasonic G and GH series body are neither. Panasonic had to accommodate item 2 video handling and to do that needed to include an heatsink in their models and this makes the shape of the GH5 large. Then they continued that trend with the G9: both cameras are very similar to an APSC DSLR and larger than Sony A series.

Olympus never cracked the video space, their cameras are limited in that respect while Panasonic has scored significant success and now brands like Zcam and Blackmagic Design use MFT sensor for semipro cinema cameras that perform very well in that segment.

So MFT has not disappointed as a whole, though Olympus seemed to have lost track of the manifesto, and ended up competing in territories where other players are already consolidated. It has to be said they have done that on their own accord as the OMD EM-1 MKII is a very capable camera for who does not want to invest in a large rig and with a battery grip gives you pretty much the same of the EM1X at half the cost or less at today prices.

What happens next?

It is worth looking at what is in scope and what is the envisaged structure of the imaging division after the carve-out.

Scope

There is mention that the prestigious brands of OMD and Zuiko will continue with NewCo. In short this means that OMD and Zuiko that really were product lines become brands. This is because Olympus corporation will continue and therefore NewCo cannot be called Olympus cameras or similar. There is no mention of Pen or Tough lines to be in scope of the transaction specifically, this may be simply omitted or those are not in the interest of JIP.

NewCo will also maintain the R&D and manufacturing functions, this is important as otherwise product development would not be possible. We need to understand practically what does this mean in terms of key people and which one will move along and which one will leave.

Timetable

JIP is currently performing diligence and, subject to confirmation of their assumptions, the deal would be signed at the end of September and then close at the end of 2020. JIP has now access to Olympus data and financials and this will help them confirm their offer, but potentially could also mean they back off if the situation is worse than expected. Olympus has also committed to continue the restructuring already in progress, this is important as that has an impact on the valuation of the business.

Transition Agreements & Rebranding

When the transaction is complete it is possible that there are still dependencies on the seller and therefore transitional service agreements are put in place. It is easy to imagine that those will go ahead for 18 to 24 months and the largest question mark is up to which point the NewCo will be allowed to use the Olympus brand and how they are going to deal with re-branding. Re-branding can be lethal to businesses I do not want to provide a long list but there is an intangible value to the name of a brand and is not simple to switch consumer to the new brand and keep them all, people sometimes, actually most times, go elsewhere and Panasonic will most definitely benefit from this.

The immediate future

Usually when those type of transactions are announced there are all sorts of activities to say that is business as usual, things will get better and products roadmaps and other events are promptly coming out to reassure consumers. The prime reason for that is that consumers may want to switch right now or if they were planning to buy this specific brand they may change their mind. The reality is that carving-out a business is not easy and nobody really knows how things will turn out.

Micro Four Thirds Future

The crisis at Olympus is not a good thing for Micro Four Thirds there is no doubt about it, however this should not be too much of a worry for day to day life. DSLR has been pronounced dead years ago but is still there and MFT is an important step towards mirrorless. It is evident that cameras will eventually move towards mirrorless and the advances of Olympus cameras on autofocus are an important step, today only Sony and Olympus have decent autofocus on mirrorless. Canon and Nikon are playing catch up but their pro equipment is still DSLR.

The market is shrinking and Olympus is not going to be the last company to struggle, who will survive is not necessarily linked to who has the best product, but to those who can manage the market situation and can align to consumer needs.

ambient light, MFT Lenses, Micro 4:3

Why You need 1.4 lenses on Micro Four thirds

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This post is NOT about underwater imaging. With the lockdown most of us have started using their cameras in the garden to shoot bugs, or birds or family members or abstracts.

In my instagram on the side you can see some examples of what I have been up to.

Shooting underwater is typically done at small apertures because of underwater optics issues. It is rare to shoot wide angle wider than f/5.6 on a MFT body or F/11 on full frame.

On land everything changes and you want to have as much light as possible coming into your camera to maximise dynamic range, bring out colours and minimised noise. Aperture controls not just how much light hits the sensor but also depth of field or I should say depth of focus.

Depth of field at equal level of magnification (size of the subject relative to the frame) depends only on the aperture of the lens. It does not matter if the lens is short or long once the subject fill your frame it is the f/number that influences depth of field.

2.8/2/1.4 is the Magic Number

Typically in full frame terms f/2.8 was a good lens, and the reason is quite simple if you shoot a classic 50mm lens from 1.5 meters away you will have 15 cm or half a foot depth of field. This is ideal to keep things in focus but also provide some background separation as objects blur as they move away from the area in focus. If you had a faster lens more light would go in the frame however you risk that nothing is in focus, for example nose and eye in focus and maybe ears not in focus.

And this is why 2.8 has been the magic number for full frame photography. If we move to an APSC sensor this becomes 2 and on MFT the magic number is 1.4. So 1.4 on a 25mm lens on MFT is equivalent to 2.8 on 50mm on full frame.

-20200211-13.jpg
Street Photography Night scene at 1.4

1.4 also gives plenty of light to your sensor so when you want to do some street photography or filming on MFT you can keep your ISO very low.

Exposure Value

Every scene has a level of illumination given in LUX and your camera needs to be able to expose for it with the right focus, with the required motion blur and lowest noise.

The scene in the image above is shot at f/1.4 1/60 ISO 640 let’s calculate the Ev taking into account the reference value is f/1 1 second and ISO 100.

1.4 means 1 stop 1/60 means 5.9 stops and 640 means 2.67 stops. So in total we have 6.9 stops of light taken away from aperture and shutter and 2.67 stops added by ISO gain. Total of 4.22 Ev using the formula Lux = 2.5 2^Ev we get 47 Lux which is the level of illumination of your living room in the evening with artificial lights.

If you had a slower lens like for example 2.8 to cover the same scene you needed to shoot at ISO 2500 this would have increased the noise, reduced the dynamic range and the colors.

2.8 Zooms are for outdoor

There are a number of great lenses for MFT cameras that are midrange zoom and have outstanding optical quality:

Panasonic 12-35
Olympus 12-40

The lenses above are constant aperture and weather sealed they are ideal for outdoor use however they do not offer a shallow depth of field for subject isolation as they really are f/5.6 in full frame equivalent and they are also slow meaning they will take you to the ISO 2500 zone if you try street photography or shooting movies in your living room.

Prime Rules

If you want fast lenses in MFT you need to have prime lenses, this is due to the physical constraint of the format.

Here my selection, I am not a fan of vintage lenses or full manual lenses, I like the best optical quality and if I want to add a vintage feel I do it in post.

From left: Panasonic 12mm, Sigma 16mm, Panasonic 25mm, Panasonic 42.5 all (at least) 1.4 lenses

In more detail:

Panasonic 12mm 1.4

The Panasonic 12mm 1.4 is an expensive lens that I use for astrophotography and gimbals plus low light narrow room indoor shots.

It is weather sealed, extremely sharp and fast to focus and works in full auto focus on a gimbal.

Home Sweet Home
Star Trail with 12mm 1.4
Gimbal
Sigma 16mm 1.4

The Sigma 16mm 1.4 must be the best value prime on the market for MFT lenses. I use it in street photos and for videos. It is almost a 35mm full frame lens.

-20200213-11.jpg
street photography with Sigma 16mm
Garden Overview
Panasonic 25mm

The Panasonic 25mm is a workhorse for small group portraits and ideal lens for movie style video.

25mm 1.4
Kids video with 25mm
Nocticron 42.5

The Panasonic 42.5 Nocticron is probably the best portrait lens on MFT and one of the best lenses overall. It is an f/1.2 lens however in terms of actual transmission performs the same as f1/.4 lenses but with better rendering of out of focus areas.

Nocticron portrait

Why not Olympus/Others?

Of course there are equivalent primes from other brands for all focal lengths except the 12mm. They will perform equally and as long as they can go to 1.4 all is good. I use Panasonic bodies so tend to have Panasonic lenses and I buy Sigma since a long time but this is personal. There are tons of reviews on which lenses to choose etc etc but is not my place to do such comparisons. Edit since Olympus giveaway promotion in 2020 I have replaced the Sigma 16mm 1.4 with the Olympus 17mm 1.2 as they are equally bulky. The Oly pro is a fabulous lens but at the RRP suggested not affordable for many.

How about Video?

Even more essential to have fast primes for video as you are constrained in the shutter speed you can use.

Using a 1.4 lens at 1/50 you can shoot several scenes at different ISO

ISOLuxTypical Scene
200125Dark day
40063Indoors low lit areas
80032full overcast sunset/sunrise very dark indoor
160015Near twilight
32008After Twilight dark
64004dark
128002very dark
256001Candlelight
Aperture vs environment

For my purposes this adequate for reference underwater scenes at 3.5 means I can cover 100 Lux in ambient light in movie mode before turning on the lights.

Conclusion

If you find yourselves with grainy images or videos invest in fast lenses. A lens is the eye of your camera and the sensor is the brain. Think about getting better lenses before investing in a new camera and consider that if you need to go in lower light it is not always true that getting a bigger sensor will help considering the limitation of depth of field so you may want to think about lights.

Canon EF lens, Fisheye lens, Micro 4:3, Panasonic GH5, Underwater Photography

Canon 8 – 15 mm Fisheye on the Panasonic GH5 Pool Tests

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It was time to get wet and test the Canon 8 – 15 mm fisheye on the GH5 in the pool so I made my way to Luton Aspire with the help of Rec2Tec Bletchley.

I had the change to try a few things first of all to understand the store coverage of the fisheye frame, this is something I had not tested before but I had built a little model.

In purple the ideal rectangle built with the maximum width and height of the fisheye frame

This model ignores the corners the red circle are 90 degrees light beams and the amber is the 120 degrees angle. A strobe does not have a sharp fall off when you use diffusers so this model assumes your strobe can keep within 1 Ev loss around 90 degrees and then drop down to – 4 Ev at 120 degrees. I do not want to dig too deep into this topic anyway this is what I expected and this is the frame.

Shot at 1.5 meters from pool wall

You can see a tiny reflection of the strobes together with a mask falling on the left hand side… In order to test my theory I run this through false colour on my field monitor, at first glance it looks well lit and this is the false colour.

False colour diagram of previous shot

As you can see the strobes drop below 50 at the green colour band and therefore the nominal width of those strobes is probably 100 degrees. In the deep corners you see the drop to 20 % 10% and then 0 %.

Time to take some shots

Divers hovering @ 8 mm

The lens is absolutely pin sharp across the frame, I was shooting at f/5.6 in the 140 mm glass dome.

Happy divers @ 9 mm
BCD removal @ 10 mm
Gliding @ 11 mm
Open Water class @ 12mm
Divers couple @ 13 mm
Hover @ 15 mm

Performance remains stunning across the zoom range. I also tried few shots at f/4

9 mm f/4

There is no reef background but looks pretty good to me.

The pool gives a strong blue cast so the shots are white balanced.

If you want details of the rig and lens mount are in a previous post

Fisheye Zoom for Micro Four Thirds

Panasonic GH5 zoom fisheye rig
Canon EF lens, Fisheye lens, MFT Lenses, Micro 4:3, Panasonic GH5, Sunbursts, Underwater Photography, wide angle

Fisheye Zoom for Micro Four Thirds

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Looking at Nauticam port chart the only option for a fisheye zoom is to combine the Panasonic PZ 14-42 with a fisheye add on lens. This is a solution that is not that popular due to low optical quality.

So micro four thirds users have been left with a prime fisheye lens from Panasonic or Olympus…until now!

Looking at Nauticam port chart we can see that there is an option to use the Speedbooster Metabones adapter and with this you convert your MFT camera to a 1.42x crop allowing you to use Canon EF-M lenses for cropped sensor including the Tokina 10-17mm fisheye. This is certainly an option and can be combined with a Kenko 1.4x teleconverter giving you a range of 14.2 to 33.8 mm in full frame equivalent or 7.1 to 16.9 mm in MFT terms fisheye zoom of which the usable range is 8 -16.9 mm after removing vignetting.

A further issue is that the Speedbooster gives you another stop of light limiting the aperture to f/16 while this is generally a bonus for land shooting in low light underwater we want to use all apertures all the way to f/22 for sunbursts even if this means diffraction problems.

Wolfgang Shreibmayer started a trend time ago in WetPixel https://wetpixel.com/forums/index.php?/topic/61629-canon-ef-lenses-on-mft-cameras/ to use full frame lenses and in this post I want to do a deep dive on what is for me the most interesting lens option the Canon 8-15mm fisheye.

This lens on full frame can be used for a circular and diagonal fisheye but Wolfgang has devised a method to use it as an 8-15mm fisheye zoom on MFT.

Part list – missing the zoom gear

What you need are the following:

  • Canon EF 8-15mm f/4L fisheye USM
  • Metabones Smart Adapter MB_EF_m43_BT2 or Viltrox EF-M1 Adapter
  • A 3D printed gear extension ring
  • Nauticam C-815Z zoom gear
  • Nauticam 36064 N85 to N120 34.7mm port adapter with knob
  • Nauticam 21135 35mm extension ring with lock
  • Nauticam 18810 N120 140mm optical glass fisheye port

The assembly is quite complicated as the lens won’t fit through the N85 port. It starts with inserting the camera with no lens in the housing.

GH5 body only assembly
Camera in housing without port

The next step is to fit the port adapter

Attach N85 N120 Metabones adapter

Then we need to prepare the lens with the smart adapter once removed the tripod mount part.

Canon 8-15 on Metabones Smart Adapter IV

As the port is designed for the speed booster the lens will be few mm off therefore the gear will not grip. Wolfgang has devised a simple adapter to make it work.

gear extension ring
Zoom gear on lens

This shifts the gear backwards allowing to grip on the knob.

3D design is here

Lens inserted on housing

Looking at nauticam port chart an extension ring of 30mm is recommended for the speedbooster and now we have extra 5mm in length Wolfgang uses a 35mm extension. however looking at the lens entrance pupil I have concluded that 30mm will be actually better positioned. Nauticam have confirmed there won’t be performance differences. You need to secure the ring on the dome before final assembly.

Fisheye dome and extension
Full assembly top view
Side front view

The rig looks bigger than the 4.33 dome but the size of the GH5 housing is quite proportionate. It will look bigger on a traditional small size non clam style housing.

The disassembly will be made again in 3 steps.

Disassembly

I am not particularly interested in the 1.4x teleconverter version consider that once zoomed in to 15mm the lens is horizontally narrower than a 12mm native lens so there is no requirement for the teleconverter at all.

This table gives you an idea of the working range compared to a rectilinear lens along the horizontal axis as diagonal is not a fair comparison. The lens is very effective at 8-10mm where any rectilinear would do bad then overlaps with an 8-18mm lens. The choice of lens would be dictated by the need to have or not straight lines. The range from 13mm is particularly useful for sharks and fish that do not come that close.

Focal lengthHorizontalVerticalDiagonalHorizontal Linear EqWidthHeightDiagonal
8130.995.9170.217.31321.64
9114.984.7147.8
10102.575.9131.06.9
1192.668.7117.88.3
1284.562.9107.29.5
1377.757.998.410.8
1472.053.790.911.9
1567.050.184.613.0

Wolfgang has provided me with some shots that illustrate how versatile is this set up.

8mm end surface shot
Caves 8mm
15mm end close up
Dolphins at 15mm
Diver close up at 8mm
Snell windows 8mm
Robust ghost pipefish @15mm

As you can see you can even shoot a robust ghost pipefish!

The contrast of the glass dome is great and the optical quality is excellent. On my GH5 body there is uncorrected chromatic aberration that you can remove in one click. Furthermore lens profiles are available to de-fish images and make them rectilinear should you want to do so.

I would like to thank Wolfgang for being available for questions for providing the 3D print and the images that are featured here on this post.

If you can’t print 3D and need an adapter ring I can sell you one for £7 plus shipping contact me for arrangements.

Amazon links UK

Canon EF 8-15 mm f/4 fisheye USM lens

Viltrox EF-M1 Mount Adapter

Note: it is possible to use a Metabones Speed Booster Ultra in combination with a Tokina 10-17mm zoom fisheye and a smaller 4.33″ acrylic dome.

UK Cost of the canon option: £3,076

Uk Cost of the Tokina option: £2,111

However if you add the glass dome back

UK Cost of Tokina with glass dome: £2,615

The gap is £461 and if you go for a Vitrox adapter (would not recommend for the speedbooster) the difference on a comparable basis is £176 which for me does not make sense as the Canon optics are far superior.

So I would say either Tokina in acrylic for the cost conscious or Canon in glass for those looking for the ultimate optical quality.

MFT Lenses, Micro 4:3, Panasonic GH5, Tips, Underwater Photography, wide angle, Wrecks

Using Rectilinear Wide Lenses Underwater

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I was checking the technical details of Alex Mustard Underwater Photography Master Class and the majority of wide angle pictures are taken with a fisheye lens. In the section about shooting sharks Alex says that he prefers to shoot sharks with a fisheye otherwise they look ‘skinny’.

If you look online on underwater video forums you frequently see comments on problems with wide angle lenses connected with the use of a rectilinear wide angle lens in a dome.

The two most common complaints are soft corners and distortion.

Soft corners are due to a combination of lens optical issues and dome port optics. In short any lens is to some extent curved and therefore if you shoot a flat surface the image may be sharp in the centre and softer as you move to the corners. Issues with field of curvature are corrected stopping down the lens. The issue with field of curvature happens everywhere not just underwater.

Right now there are four wide angle lens that can be housed for a micro four third camera:

Olympus 9-18mm

This lens has a nice working range that allows to capture 100 degrees diagonal at widest setting and still has a 35mm equivalent at the tele end. This is a pretty little lens at $699 is the most affordable option that can be put in a housing. You will need a wide angle port and the zoom gear. The whole combination for your Nauticam housing comes at $1,399. This lens can also be combined with a glass dome but this will make the whole combination much more expensive and you may want to think about getting a better lens instead.

Olympus 7-14mm

This is an outstanding lens especially on land due to the fast f/2.8 aperture. It is expensive at $1,299.99 and very heavy and bulky. The lens does not fit through the N85 port opening and requires a port adapter this gives the extra benefit of a focus know but with such a wide lens is not really useful due to high depth of field. You will need a 180mm glass dome and the zoom gear for the lens to complete the set up ending at a whopping $3159.99.

Panasonic 7-14mm

I have owned this lens and I have to say that at $799 is the right compromise between wide field of view and price. Furthermore once you get the zoom gear you have the option of a cost effective acrylic dome that will give you a very wide set up for $1589.99. There are reports of poor performance with this lens and it is true that is not as sharp in corners but the results are perfectly acceptable if you stop at f/8 in close shots.

Steering Wheel Truck
Panasonic 7-14mm with acrylic dome 9mm f/8
Exploring the Chrisoula
Panasonic 7-14mm with acrylic dome 7mm f/5

This lens is prone to reflections and flare however once you add the N120 port adapter and the 180mm glass dome this will get you to $2819 at that point you may want to consider the Olympus combination instead.

Panasonic Leica 8-18mm

This is my favourite lens is sharp does not suffer from field of curvature issues and has a very useful zoom range 16-35mm in 35mm equivalent. The zoom gear and the 7″ acrylic dome will take you to 1889.99 that is an excellent price point. The lens is not prone to reflection or flare and as the 7″ dome has the same curvature radius than the 180mm dome it will produce very similar results.

Encircled
Panasonic 8-18mm in 7 acrylic dome f/8
Sunset Neat
Panasonic 8-18mm at 8mm f/10

The significant size of the acrylic port and the fact it floats make it ideal for split shots and this is the lens that gives me the best results.

This lens can also take port adapter that allows you to use the 180mm glass dome. This adds up to $2919.99 if you experience bad reflections and shoot frequently in the sun it may be worth it but I have not had any issue so far with this lens probably because of its nano coating.

I have found the 7mm focal length too problematic for dome ports and the amount of perspective distortion excessive generally it would be preferred to shoot at 9mm and narrower however this maybe insufficient for wreck interiors if you want a rectilinear look.

Perspective Distortion

One of the regular complaints of video shooters especially in wrecks or caves is that the edges look horrible and distorted and that there is an issue with the corners pulling. This is in fact not an issue but a problem with perspective as you shoot very wide angle. The following test shots will illustrate that the issue happens on land and has nothing to do with dome ports.

Shot at f/2.8 with Panasonic 8-18mm at 8mm shows sharp corners
Image with objects in edges at 8mm

As we can see the football looks like an oval and the chair is pulled. This is due to a perspective issue and is not a lens problem. When you shoot underwater video the objects on the edges of the frame change shape creating this pull effect that most people dislike.

Same scene at 9mm

At 9mm the amount of perspective distortion is reduced and this is the reason why 18mm on 35mm equivalent is one of the favourite focal length for rectilinear video and the maximum angle that should be used in small spaces to avoid the pulling edges.

One of the reason why a lens like the Nauticam WWL-1 is preferred for video is because the corners look sharp but is that really true?

Not really let’s apply some barrel distortion to simulate the WWL-1 to the image that looked badly distorted.

Barrel distortion applied -60 8mm

Now the football looks circular as we have applied -60 barrel distortion, obviously the rest of the image is now bent but this seems not to be of a concern to most people!

Barrel distortion -30 9mm

It needs much less correction to bring the 9mm shot into shape and for sure between the 8mm and 9mm the 9mm is the dimension that produces the most acceptable results.

It has to be said that in video with 16:9 aspect ratio most of the issue will be cropped away at the edges but the distortion in the middle of the frame will remain. For the same reason the 9mm image will appear practically rectilinear with no issues

16:9 crop still showing the edge ‘pulling’ at 8mm

16:9 crop looks straight at 9mm

I hope this post was useful there are four options for micro four thirds shooters to use rectilinear lenses I have settled for the Panasonic 8-18mm as in most cases it is still possible to control the perspective issue, I found this impossible at 7mm.

Bike on Hold 2
Bike in hold 2 on SS Thistlegorm Panasonic 8-18 at 8mm
Bubbling Bike
Shot at 7mm showing the front tyre pulling outside the frame

Obviously if you shoot in the blue this problem will not be visible however rectilinear lenses are popular with wreck shooters and I think this posts gives an idea of the challenges at play.

Finally I would discourage the use of the 7-8mm focal length range for video to those that want to have a rectilinear look.

From this post I started supporting Bluewater Photo in US for my links because it still provides multi brand and choice and because I learnt a lot from Scott Gietler Underwater photography guide back in the days where there was no internet resource to learn from.

close up lens, diopters, Fish Portraits, Flat Port, macro, MFT Lenses, Micro 4:3, Panasonic GH5, Underwater Photography, UNDERWATER VIDEO, Wet lenses

which macro lens to pick for your gh5 or micro four third

1 Comment

I see many posts on line debating which macro lens is best for your micro four third system.

If I refer to the Nauticam system we have 4 macro lenses:

  • Olympus 30mm
  • Panasonic 30mm
  • Panasonic 45mm
  • Olympus 60mm

For the purpose of this article I will skip the Olympus 30mm as the Panasonic lens is known to be sharper and will focus on the other 3 lenses.

DxOMark is a popular tool for comparison as it gives you the results on one page. I have run it for the Oly 60 and the Pana 30 and 45 on the 20 Mpix OMD E-M1 MKII

DxOMark Comparison on Olympus OMD E-M1 MKII

Surprisingly the much more expensive Leica performs worse than the other cheaper models, this is confirmed on all internet sites running other type of tests.

What we can see is that there is little difference between the Panasonic 30mm and Olympus 60mm when it comes to image quality so whichever lens you choose your subject at the same level of magnification and aperture will have more or less the same detail.

Common Misconception: Shorter focal length give more depth of field

Many people think that using a longer lens is harder because there is less depth of field this is actually incorrect conceptually.

Let see why

Using an online calculatore like Dofmaster https://www.dofmaster.com/dofjs.html

Enter for the Panasonic GH5 the following parameters

Circle of confusion: 0.015 mm

Focal length 30mm

Distance 10.5 cm (minimum distance of the 30mm Macro)

Aperture f/11

Result Total depth of field 0.3cm

Now enter

Focal Length 60mm

Distance 21 cm (as it achieves the same magnification)

Aperture f/11

Result Total depth of field 0.3cm

So depth of field is not a consideration when choosing a macro lens…

Shooting a subject close to the background

In the following 3 shots am taking an image of a widget at f/11 at 29-44-60 mm on a Leica 12-60 (it is just easier it makes no difference to the outcomes)

Shot at 60mm
Shot at 44mm
Shot at 29mm

At the same aperture you can clearly see that there are no difference whatsoever in the detail and actually overall in the picture you don’t notice anything.

Shooting a subject far from the background

For the second shot I have moved the widget away from the wall.

Shot at 60mm
Shot at 44mm
Shot at 29mm

Again there is no difference in the level of detail of the widget however looking at the background we can see that

  • The 60mm shot reveals one brick and less than one quarter
  • The 44mm shot reveals one brick and a half
  • The 29mm shot reveals two bricks

So while the subject is exactly the same as the 60mm lens has a narrower field of view we see much less of the background.

This means that if you are shooting a nudibranch on the sand or something flat on a rock you won’t notice anything however if there is space behind the subject you will capture much more of that resulting in less subject isolation.

Underwater Comparison 30 vs 60 mm

In the first shot the Rhinopia is taken with a 60mm lens

Rhinopia Olympus 60mm

In the second shot the same Rhinopia with the 30mm (in a different place to be fair)

I have marked up with red the areas that with a longer focal length would have been minimised.

Which Lens to choose?

Now that we have clarified that depth of field is not a consideration and as each macro lens will have the same magnification there are only two factors that matter:

  1. Working distance
  2. Isolation from background

The 60 mm will have a longer working distance and at the same magnification will isolate the subject better from busy backgrounds, the 60 mm is also better for skittish subject because of the longer working distance. I have this lens and I have borrowed the 30mm in couple of occasions but do not have the 30mm yet.

There are however situations where longer working distance is not a benefit, specifically when the visibility is poor and there are suspended particles or the subject is really large.

In the example below I was at one meter from the two frogfish, a 30mm would have been better however the shot came OK.

Hairy frogfish Olympus 60mm

Conclusion

I believe the Olympus 60mm is a must lens to have. To date I have not felt the need for the Panasonic 30mm that is indeed a very sharp lens because I have always managed to pull out the shots. However for someone diving in murky water and focussing on nudibranches or subject laying flat on the seabed the Panasonic 30mm could be a better choice. I also want to say that using the 14-42mm at 42mm for me is actually a better choice for portraits and with a close up lens works very well with small subject not super macro and therefore as I already own the 14-42mm and various diopter for me the 30mm is not on the shopping list.

ambient light, filter, Micro 4:3, Panasonic GH5, Underwater Photography, UNDERWATER VIDEO, Video Lights, Wet lenses, White Balance, wide angle

Getting the best colors in your underwater video with the panasonic gh5

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There is no doubt that the Panasonic GH5 is a very capable camera and in given conditions the video performance you can get is truly impressive.

Broadly speaking a video clip needs to be:

  1. Sharp
  2. Colorful
  3. Contrasty
  4. Clean

Those 4 characteristics are tightly related to:

  1. Resolution
  2. Color depth
  3. Dynamic range
  4. Low Noise

Resolution

Today everyone shoots 4K and after all resolution is well supported by almost any camera, broadly is unaffected by other factors and unless the noise is really high sharpness of your frame is not going to be a real issue shooting at 4K.

Color depth

In normal conditions and not underwater a camera can resolve many colors. However underwater due to the diffraction of light and selective absorption of colours the starting point is very different from land. So generally is not the camera that cannot resolve the colors but the colors that are missing to start with. This post will focus specifically on this aspect. The Panasonic GH5 can resolve 23.8 bits in RAW and therefore technically has less than 8 bits color depth – do not confuse this with the 8 or 10 bit recording setting.

Dynamic Range

Underwater scenes tend to have limited dynamic range, with the exception of sunbursts or shooting against the light this is going to be an issue only in specific circumstances of very bright scenes with shadows. In all scenes taken with video lights dynamic range is not an issue at all. The GH5 has 13 stops of dynamic range but rarely this is an important consideration.

Noise

Noise is an important consideration as when the noise goes up the camera looses the other characteristics, color, dynamic range and resolution will be affected when the camera is outside the sweet spot. Broadly speaking the Panasonic GH5 does not do well once you pass the ISO 1600 setting and I tend to cap the ISO in video at 800 in most cases.

Diving Conditions

To understand how those variables play we can see how the same set up reacts very differently in scene where there is less light and therefore the camera uses high ISO like this one.

The same camera with exactly the same equipment in brighter water produces this

So the reason for the above is that with less light there are less colours and the clip looks what it is really.

OK moving on to the main subject of this post how do I get the colors right? It is a combination of techniques and the trick is to use the right one in the right conditions.

Generally every site has specific conditions that change depending on weather, time of the day, visibility and other factors. So in broad terms a site will have more or less light and therefore more or less colours. It is therefore impossible to categorically define what to do at a given depth but is more about typical values. With this in mind we have typically 3 scenarios:

  1. Ambient light shots
  2. Artificial light shots
  3. Balanced light shots

Close up Shots

In general close up shots especially of small subject fall within the scenario 2 for which a video light with high color rendering is important as this will define the colours you see. With a lot of power it is possible to extend artificial lighting to larger subjects but eventually you run out of power due to distance or size of the subject.

Wide angle shots and seascapes

True wide angle shots are generally ambient light shots which also means when it gets too dark the colors will be missing and it will look blue not matter the equipment.

In order to make the most of ambient light shots for wide angle it is essential to balance the colours in water even when you use a RAW format on a still image because RAW files are not as RAW as you think and are actually compressed.

Custom White Balance

Using Custom White balance with a grey card it is possible to obtain decent results until the camera hits the maximum color temperature in the case of the Panasonic GH5 this is 9900K. Depending on conditions you may get to 10-12 meters and this still works, in darker water this stops working much sooner.

Chrisoula K Bow
Chrisoula K Ambient Light 5 meters

Color Filters

Color filters push the limit of custom white balance further down. Some add more or less 4 meters others up to 6-8 meters at the expense of an overall loss of light. Filters are useful when there is a lot of light because also help to keep the Panasonic Gh5 in the best aperture range (not smaller than f/11)

Filter in action at 10 meters

Right now there are predominantly 3 filters on the market:

  1. UR PRO
  2. Magic filter
  3. Keldan Spectrum

All those filters will improve the performance and color rendering of your footage, under the conditions that the loss of light is not pushing the camera above reasonable ISO values.

In terms of depth range the magic filter and the Keldan Spectrum -2 version can be pushed to 15 meters depth on a bright day in clear water. The URPRO is capable of getting a few meters more down to around 17-18 meters although it does generate an orange cast (as there is no red left) it is still workable.

FilterLight LossTypical Max Depth
Magic Filter1 2/3 Ev15 meters
Keldan Spectrum -22 stop (WWL)15 meters
URPRO 1 2/3 Ev18 meters

This image gives an idea of the 3 filters as you can see they are very different one from the other.

Keldan top URPRO bottom Magic filter

Balanced Wide Angle Shots

This is an entirely new technique that has started with the Keldan Ambient light filters. I wrote a whole piece on wetpixel

The principle is to use custom white balance with or without filter to obtain color rendering and then put filters on the video light so that the color of the light emulates the ambient light and therefore it only gives texture not color.

Keldan has developed a whole range of filters for various situation that match their light and therefore are not applicable to any other light.

As I do not own a set of Keldan I have done some tests and found that a gel of Cyan filter 2 or 3 stops makes my divepro G18+ practically ambient light in the conditions I dive into.

FilterCyan Strength
Magic Filter2 stops
Keldan Spectrum2 stops
URPRO3 stops

The above value are based on my experience use at your own risk especially with different lights.

Square Cyan 2 stops Round Cyan 3 stops

To give an idea I overlapped the filter to my iPhone lens

This is the shot without any filters

Original Shot

URPRO and Cyan 3 stops (darker)
Magic filter and cyan 2 stops accurate
Keldan and cyan 2 stops accurate

This example shows that the two filters cancel themselves the result is almost daylight with no cast which means in water if you use a video light or a strobe you will not see a red or orange spots on the image.

For those taking pictures the same combination remains true with Inon Z240 and Sea and Sea YS-D2

Example picture here

five in a row
My own filter and Cyan 3 stop note that the light is coming from the other side

One thing to take into account is that you need to find a way to hold the gel on the video light or the strobes. The flat surface strobe diffusers make this process easy, finding something you can use with your video lights is not easy and also the gels may melt after continuous use.

Artificial lights

It comes a point and a depth where filters stop working, this could be as shallow as 8 meters in green water. As the scene is dark using lights is what is required. There is nothing specific about this technique except making sure you don’t get burned highlights or backscatter. As it happens in photography using long arms (maybe not as long as for stills) is key to get good lighting on your subject.

My Camera Settings

I use CineLike D with saturation, sharpness and noise reduction to -5. I shoot at 24/25p AVCI 400 mbps and follow the 180 rules, it is entirely possible to shoot at 1/100 if you like more crisp look.

Clearly there are people out there that do not like filters and think white balance is best etc but I think a good read on magic filters explains it all.

http://www.magic-filters.com/need.html