Tag Archives: Underwater Video

Panasonic GH5S Review – Conclusion

I hope you found the tests useful and I guess the key question is:

Is the GH5S still worth it in 2022?

I have prepared a comparison table with the GH5 and GH5M2 using data available and for noise my subjective measurements supported by the video evidence.

As you can see from the table the GH5S still has some unique features:

  • RAW support (ProRes RAW and BRAW)
  • VLOG performance
  • High ISO performance straight out of camera
  • Slightly lighter and better battery life

So if any of the above are essential to you there is still a case for the GH5S.

However the GH5M2 with Neat Video will cost you $1,699+$129=$1,828, for sure you will have to work without Vlog and RAW but you will have many other benefits and you will not need a recorder to shoot 50/60 fps bringing the overall cost down significantly.

Panasonic GH5S long overdue review – Part III Low light Field Test

For part 3 of my test I ran the GH5S side by side with GH5M2 with the same settings used for daylight. The GH5S used VLOG which is the best photo style for it while the GH5M2 used CineD2, again the best photo style for it. Bear in mind if you had run this comparison with both cameras on VLOG the GH5S would have trashed the GH5M2 at high ISO because the implementation of VLOG in the GH5M2 is simply not performing.

The two cameras were set in multi metering with focus at hyperfocal distance. I tried to match the field of view using the 10-25mm on the GH5M2, make no mistake the PL 15/1.7 I used on the GH5S is an amazing and very sharp lens. Both cameras were set to auto white balance and I put the GH5M2 in auto ISO because it shows on screen the value it is using while the GH5S was set in complete manual. Whenever the GH5S was displaying a negative value on the meter I would increase ISO 1/3 Ev. The GH5M2 was left to deal with it in auto as I had previously confirmed the meters were aligned, or at least this is what I thought until this test.

GH5S left and GH5M2 right

I started all the way from ISO 200 and waited until night fall.

If you want to watch the video and form your own view here is the link. You will need a Tv with zoom function to be able to see the fine details.

My expectation was that the cameras would perform almost the same until ISO 1600 at that point the dual gain of the GH5S should produce better results. I will spare the analysis at lower ISO values as it does not really say much.

Analysis

As explained in the video you need to focus on three part of the image. The top part and any residual tone of the sky tells you if the camera is loosing DR. The tables at the bottom are a sign of loss of detail due to noise but also of possible temporal noise reduction. Temporal noise is a flickering resulting from noise scattered differently in the frames. When the image retains detail but has this flicker it is said to have temporal noise. If the clip looks stable but lacking a bit of edge details it is a sign of potential temporal noise reduction in camera.

Due to the lower pixel count temporal noise reduction in the GH5S would perform better than in a higher pixel count camera.

ISO 1250

Here the GH5S is in low gain and my expectation was performance to be very similar. At this ISO value the GH5S retained good detail however showed more noise in each part of the frame.

GH5M2 Moving Detail
Same detail on the GH5S note the added chroma noise

The noise levels appear identical in the static parts of the frame.

GH5M2 static detail

All in all at ISO 1250 the situation appears very similar the GH5S has a bit more noise but still have detail compared to the GH5M2.

ISO 2000

The light dropped suddenly so I did not manage to record the ISO 1600 step on both camera at the same time as I was distracted by external factors (had to order at the bar).

GH5M2 detail at ISO 2000
GH5S ISO 2000

Although the noise appear similar I would say the GH5S retained more detail at ISO 2000, consider the observation is far away and on the edges of the frame so it is a difficult scenario.

GH5MS static detail
GH5S static detail

Looking at the static part gives a different picture with the GH5M2 having an edge and the GH5S smudging details.

ISO 2500

I was expecting the GH5S to be a clear winner at its second native ISO.

GH5M2 detail birds moving
GH5S detail

The part of the frame with motion did not show a much better detail for the GH5S while the static part looked cleaner.

GH5M2 static detail
GH5S static detail

This behaviour makes me think that the GH5S has a stronger temporal noise reduction filter. When it does not detect motion it goes down hard resulting in a very clean image. When it does detect movement it becomes more cautious especially if the moving parts use only a small area. This would explain the mixed behaviour in the ISO 2500 situation.

Overall I was expecting much better performance and a clear difference between the two.

ISO 3200

My expectation was that as the ISO was going up the gap between the two cameras would have increased however at ISO 3200 I was surprised to see the GH5M2 made a recovery and the quality is almost identical.

GH5M2 ISO 3200 motion detail
GH5S motion detail

In addition I can see the GH5S noise reduction starting to eliminate some details when it can’t quite work out what to do. Look at the table tops near the two walkers in the frame.

GH5M2 Static detail
GH5S static detail

ISO 3200/4000

At this point I was presented an additional surprise the two camera started to have a gap in the metering so for a good few minutes the GH5M2 stayed on ISO 3200 while the GH5S was reaching out for more gain.

Ultimately this resulted in identical image quality in the parts with motion with the GH5S retaining some fine details better but the GH5M2 producing at the end a comparable result.

GH5M2 ISO 3200 Motion Detail
GH5S ISO 4000 Motion Detail

I won’t bore you with the static parts as they look identical.

ISO 4000/5000

The GH5M2 reached ISO 4000 however the GH5S had already moved to 5000. The consequence is that the image quality was the same.

GH5M2 ISO 4000 Motion Detail
GH5S ISO 5000 Motion Detail

Again the static parts were the same.

ISO 5000

Eventually both cameras were at ISO 5000 and here I could see a lead of the GH5S in the motion details but no benefit in the static details in terms of sharpness. However when you actually play the footage you can see the flickering of the temporal noise on the GH5M2.

GH5M2 ISO 5000 Motion Detail
GH5S ISO 5000 Motion Detail

The static details retain the same definition and resolution.

GH5M2 ISO 5000 Static detail
GH5S ISO 5000 Static detail

At this point is very clear to me that what is giving an edge up to now to the GH5S is the superior performance of noise reduction in camera as the actual dynamic range did not seem to be an element. If at all the sky becomes washed out sooner in the GH5S.

ISO 6400

From this point onwards the GH5S takes the lead however I would not say that the resulting image quality was very high. I would frankly avoid this ISO level but in desperate cases can certainly be used.

GH5M2 ISO 6400 Motion Detail
GH5S ISO 6400 Motion Detail

Perhaps more interestingly the GH5M2 although more noisy seems to preserver more details of the static part.

GH5M2 ISO 6400 static detail
GH5S ISO 6400 static detail

Noise Reduction

It became apparent during this test and you will see it clearly in the video that the GH5S has a very effective in camera noise reduction (even with NR=-5 this is still on) potentially because it does not have many pixels and can be quite aggressive with it. I tried using Neat Video with the GH5S however there was loss of detail, with the GH5M2 I could apply a temporal filter to the ISO 5000 you can see the results in the video and see what you think.

Light Levels

I was surprised to see the camera meter reading differently considering the matched set up. I also could see that the light level had to fall considerably so that the GH5S would have a benefit. In substance until both cameras were at ISO 5000 (I was using f/1.7 lenses) it did not look like the higher sensitivity of the GH5S was sufficient on its own to give a performance edge.

Higher ISO

I continued the test all the way to ISO 25600 for the GH5S the results were not exciting although you could say the camera does a decent job at showing some information. In general it seemed the camera was running out of dynamic range and also of image quality.

GH5S ISO 10000 static detail
GH5S ISO 10000
GH5M2 ISO 12800

At this point (ISO 12800) I would say that the benefit of the GH5S was now a full stop. In addition it can go to 25600.

GH5S ISO 25600

Low Light Sensitivity

I was expecting to see a material difference between the GH5S and the GH5M2 from ISO 1600 or at latest ISO 2500 with this gap growing at higher values. What I have seen instead is a bizarre progression where the GH5M2 would catch up and almost match the GH5S until ISO 4000 with a clear benefit only when the exposure was 5000 for both. It looks like in line with the aptina Dr Pix paper benefits only arrive near 0.01 lux*sec becoming higher later.

So we need 50% of ambient light * exposure time / aperture stop to be 0.01.

If we think about it f/2 1/60 this means aperture in stop is 2 which means a factor of 4. So working the inverse in order to get 0.01 lux*sec we would have 2*60*4*0.01=4.8 Lux.

If we consider an f/1/7 lens than this becomes 3.4 Lux and finally with an f/1.4 lens this would be 2.4 Lux.

In reality most f/1.4 or f/1.7 lenses really are just f/1.8 or f/2 so a value of 4 Lux for ambient light is reasonable. And this is the point where the benefit would start getting better as it goes darker. This is also consistent with my test the real performance difference started really to manifest a lot at ISO 5000 and became higher later.

We also have to consider thought that certain part of the image like the deep shadows will show a benefit sooner even if the ambient light is broadly sufficient. So it is not as clear cut as it would appear and the test confirmed such behaviours.

Conclusion

Perhaps the biggest surprise was how effective a traditional front illuminated sensor can be and how small was the gap with the GH5M2.

A key difference between my tests and others you can find on the net is that nobody actually runs tests with two cameras side by side and we have seen that at high ISO values the cameras did not meter exactly the same but what matters is the image quality at that point in time so the test still stands.

One thing has to be said though and this is that as of today if you want a micro four thirds camera style device (not a box or a cinema camera with no weather sealing) that works in low light with VLOG you are left with only one choice and that is the GH5S.

In the next part a wrap and some considerations about use cases and current competition for the GH5S.

Panasonic GH5S long overdue review – Part II Daylight Field Test

The second part of the test consisted in running the GH5S in parallel to the GH5M2 using CineD2. If you wonder why I did not use VLOG on the GH5M2 is because as discussed in a previous article VLOG on the GH5/GH5M2 is just a picture profile and does not really do anything other than deteriorate the noise in the shadows. So I used CineD2 as I wanted the maximum performance out of the GH5M2. The GH5S instead performs better in VLOG for reasons explained in the VLOG article as well.

So with the two cameras on tripods I went out for a walk and took several shots with similar exposure settings. Instead of using ISO 400 I used 200 on the GH5M2 which means the lens was one stop brighter on the GH5M2.

GH5S left and GH5M2 right

The practical tests confirmed what I was expecting based on the light box tests:

  1. The GH5S has a tendency to oversaturated reds and move blue to cyan so deep blues in the sky are almost never available. This was not so much of an issue during this test as the sky was overcast however you can see the clouds do not really have any blue tones.
  2. Auto white balance during the day performed consistently to the GH5M2 generating most times the same reading or at most a 200K difference. On this basis I do not understand why users speak about a magenta cast in some shots.
  3. The GH5S had better battery performance of the GH5M2 and I think this has to do with the LCD which is now much dimmer than the new camera as you can see in the picture.
  4. I did not see any more dynamic range in the GH5S. I would say a tad less than the GH5M2 on CineD2 at base ISO. This is visible in the second scene where I spot metered on the subject. Both camera had almost no tones left in the sky although they did not clip with the GH5M2 having perhaps an edge there.
Uncorrected out of camera waveform for the GH5S exposed to the right in VLOG
Uncorrected out of camera waveform for the GH5M2 exposed to the right in CineD2

Looking at the waveform after ETTR with the cameras showing near clipping you can see that the highlights are practically the same however VLOG has lower midtones and less darks.

This is the full video on youtube so you can make your own calls. The footage has been stretched to maximise DR ad hoc in the first scene and hues have been corrected for daylight. No other grading has been performed. In the second scene both cameras were maxed out and no further stretching has been done as it was not improving the scene.

The potential benefit of the GH5S over other models

The following table extrapolates the GH5S dynamic range considering a shift of 3dB in gain (ISO 400 -> 200 shifted)

ISO SettingGH5M2GH5SGH5Delta GH5M2 MaxDelta GH5 Max
4009.089.298.530.210.76
5038.719.048.220.330.82
6368.488.687.840.20.84
8008.178.397.530.220.86
10068.028.087.250.060.83
12737.657.766.950.110.81
16007.337.876.610.541.26
20116.907.636.300.731.33
25466.667.275.960.611.31
32006.286.995.650.711.34
40225.986.695.320.711.37
50915.646.374.970.731.4
64005.306.064.600.761.46
80455.015.714.310.71.4
101834.685.403.940.721.46
128004.335.043.590.711.45
16090
4.76

GH5M2

GH5
20366
4.39Avg0.5031251.16875
25600
4.07Min0.060.76



Max0.761.46
PDR table with gain shit

Please note this is an extrapolation I have not take measures however assuming VLOG impacts all cameras equally once gain is taken into account what you see there is that the GH5S has a potential benefit between 0.76 and 1.46 Ev over the original GH5 which is consistent with user experiences and website tests.

When you look at the GH5M2 the potential benefit drops to 0.5 and under 1600 is almost zero becoming 2/3 Ev when the GH5S is in high gain. This is also consistent to various tests on websites like dpreview and CineD.

The table does not consider however that CineD2 on the GH5M2 does accomplish more than VLOG in virtue of less noise and also does not consider the fact that some of the DR will be lost in the underexposure happening behind the scenes.

Part 2 Wrap Up

It is not difficult to see that the GH5S has good performance in daylight conditions however it does not really have any edge worth investing in it for this use case. So if you are not always at high ISO levels (>>1600) you may be getting better value from the GH5M2 that costs less takes photos and has IBIS. To be perfectly honest due to the way VLOG works I did not see major benefit even when I tested the S5 because the extra DR in the highlight was not really useful.

When we look at the GH5 instead the GH5S does remain superior but this is due to weakness of the GH5 itself. It really is quite clear that the software stack of the GH5 is really dated and the camera fairly noisy.

In the next article I will analyse two side by side shots of the GH5S and GH5M2 in low light.

Panasonic GH5S long overdue review – Part I Light Box Analysis

Since its announcement exactly 4 years ago the GH5S has been an enigmatic and successful camera for Panasonic. Today 4 January 2022 it still retails at £1,899 and it has upheld price more than the original GH5.

You would wonder who would want to get a 10 megapixel camera without stabilisation and the answer is many people that are solely focussed on video. The camera has built a reputation for low light performance and dynamic range and has been praised for its ‘color science if there is such a thing.

So after using the GH5M2 for six months I decided to rent a unit from Wex Photo and run a side by side comparison for myself.

When I say side by side I do not mean just in theory I mean in practical with the cameras close to each other and shooting the same scene.

For my tests I used a light box and a set of grey, white and color checkers and the same identical lens Panasonic 30mm macro. And for the outdoor scenes I set the GH5s with a Panasonic Leica 15mm 1.7 and the GH5M2 with a 10-25mm. As the GH5S has a multi-aspect sensor I needed to zoom the lens to less than 14mm to get the same field of view.

Before getting into the actual tests it is time to debunk a few myths about the GH5s.

Less Pixels = Less Rolling Shutter not more Dynamic Range

Camera readout is limited mostly by the speed of the Analog to Digital conversion. So having less pixels helps readout and reduces rolling shutter. This is the reason why all camcorder and dedicated cinema cameras have the minimum amount of pixels required and nothing extra.

This is true for the GH5S, the reputable website CineD as well as dpreview show a benefit of a couple of milliseconds for the GH5S over other cameras with a 20 megapixels micro four third sensor. This may be important when doing panning shots or using the camera on a dashboard or gimbal.

On the bigger pixels helping dynamic range there are a number of sources that explain why this is not the case but more importantly the the GH5S sensor has actually a quad bayer structure with cells of 4.6 microns made of 4 pixels each. So in reality the GH5S sensor has 43.64 megapixels arranged in 10.91 million cells that give 10.91 megapixels in 4:3 aspect ratio 9.07 megapixels in the 17:9 wide format. So not only bigger pixels are no help to dynamic range but the GH5S sensor actually has more pixels.

The sensor in the GH5S does not have higher dynamic range than other MFT cameras

Photonstophotos managed by Bill Claff is the only site that has measures of almost all camera models. While engineering dynamic range is purely determined by the difference between saturation signal and lowest readable signal, photographic dynamic range is what we see and is generally determined from setting a defined SNR for the image scaled to 12″ size long or 8 megapixels. This is roughly the 4K video resolution so it is a good starting point.

From this graph we can see that the G9, although based on the same sensor of the original GH5, outperforms the latter and the GH5s when it comes to dynamic range.

I am always cautious with measures taken by others so I did a full test and asked Bill to check the difference.

While in some cases there was an improvement of 0.18 Ev this would not be sufficient to push this sensor above the G9.

So the Panasonic GH5S sensor does NOT have more dynamic range of other Panasonic cameras with more pixels on the same format although it does quite well and at high ISO outperforms the GH5 at RAW level.

The multi aspect sensor has a bigger size in video but this does not improve dynamic range significantly

Due to the multi aspect ratio it is true that the sensor does not loose from a crop when changing aspect however we need to understand more what the potential benefit is.

A higher megapixel sensor with pixel of 3.3 microns will use its whole width and a cropped part of the height. If we look at 5184×2916 pixels surface this measures (5184×3.3)x(2916×3.3)=164.62 square millimeters. The GH5S with a cell size of 4.6 microns will have a surface of (3840×4.6)x(2160×4.6)=175.5 square millimeters.

Considering that dynamic range is proportional to the square root of the surface the improvement would be SQRT(175.5/164.62)=1.032 which in Stops is 0.046. So the larger area does not really do anything in 16:9 aspect ration.

In 17:9 the situation is a bit different and this benefit is 0.14 Ev still nothing so large to have a very significant impact.

During my tests I found the change of horizontal field of view which is what really matters confusing so personally I like to have a standard sensor with crop considering the benefits of multi-aspect are really limited.

The sensor of the GH5S has higher sensitivity

One of the features that the GH5S has is the so called Dual Native ISO. This is a marketing term for the Aptina DR-PIX technology which has been implemented by Sony for some time.

A white paper is here as you can read the technology enables sensors to increase sensitivity at the expense of dynamic range. The potential improvement is up to 5 dB however this is only true for very low light levels. To give an idea at deep twilight there is around 1 lux so with an exposure time of 1/50 of a second we have 0.02 lux*s this is not in the core range for this technology so more is required.

Back illuminated sensor give the additional sensitivity required as explained on Sony semiconductors page.

Now the combination of dual gain and back illumination means that the GH5S can do better at low light levels but also can tolerate very high levels of ISO. So the GH5S has additional high ISO capability for around two stops which means you can almost shoot in the dark. The key question is when does this matter when you have a fast lens.

Looking at an exposure waterfall calculator we can see that with an f/1.4 lens at 1/60 and ISO 3200 we can still cover twilight which is when public illumination is switched on.

In general terms all being equal the GH5S would have around 2/3 stops benefits in low light or in deep shadows compared to other cameras with MFT sensor.

This is quite interesting to test and quite simple using a color checker and a noise reduction software like neat video.

Here the first two samples are grey and black patches in VLOG at ISO 1600 using the Low Gain setting.

Middle Grey ISO 1600 Gain Low
Black Patch ISO 1600 Low Gain

We can see that while the noise level on the middle grey is contained the black patch jumps to 4.4.

If we take the same reading manually selecting the High Gain range we can see how the situation changes.

ISO 1600 High Gain Middle Grey

On the middle grey we are in a very similar situation. However when we look now at the black patch we can see that the level of noise has dropped significantly.

Black Patch ISO 1600 High Gain

So we can see that switching the camera from low to high gain at the same ISO has a significant benefit on darks in terms of noise.

VLOG to the rescue

With what we have said so far there has not been enough to substantiate why the GH5S would have more video dynamic range than the GH5 but VLOG comes to the rescue.

When Panasonic introduced the Varicam 35 in 2014 they were presented with the issue of having too much dynamic range.

Panasonic already have their CineLike Gamma that was able to manage 12 stops of dynamic range however this was no longer sufficient.

So the Varicam35 was provided with RAW output and with AVC Intra recording on their expensive expressp2 cards. VLOG provided an opportunity to compress the camera dynamic range in a 10 bit container that could then be recorded on card.

Panasonic made a first attempt to deliver VLOG to their Lumix with the GH4 however at 8 bit depth it did not work well. The GH5 is the first camera to have a 10 bit implementation however due to the smaller sensor it was limited to a smaller range called VLOG L which covers 12 stops of dynamic range.

A report by EBU indicates that the GH5S has more dynamic range in both CinelikeD and HLG modes compared to VLOG. Those are not scientific but are a suggestion that perhaps for a sensor with a maximum dynamic range around 12 stops VLOG is not the most efficient option. HLG presents challenges due to the color space and gamut differences however CineLike D does not require anything specific to process. Users have complained about the color accuracy of CinelikeD and generally Panasonic has been sponsoring VLOG and so have many websites under the assumption that this was the best way to preserve the full dynamic range.

While this may be true for larger sensors it would appear that this is not definitely true for the smaller MFT format.

In addition the implementation of VLOG among different camera is not the same as I already wrote here.

So in summary it is true that if you want to use VLOG the GH5S is a better option with a benefit that can be around 1 stop at high ISO over the best performing MFT camera at time of writing the GH5M2.

If you want to see the behaviour of the GH5S using a color checker you can appreciate the low level of noise at high ISO.

Color Accuracy and White Balance

I used a vectorscope to evaluate how the GH5S reproduces hues in VLOG. All tests done with factory settings and official Panasonic VLOG

You can see that the skin tone marker is exactly on target however red is more saturated than other colors and cyan is desaturated

The blue use is also shifted towards cyan.

This means that the GH5S can potentially produce a red cast and not give deep blue skies.

The weather was rubbish during my tests however from this example you can see how the red is definitely overboard by looking at the hat of the runner that comes on the scene.

This is something to watch out and a hue correction in post is required in most cases to bring things to normal.

Note that this issue with VLOG and the oversaturated red is also present in the GH5M2 that has very much the same color science or lack of thereof and will produce reddish tones on your skin that need to be corrected.

Take into account that hue correction is not resolved by setting a custom white balance.

For the hardcore pixel peepers I have shot a whole sequence of xrite color checker at all ISO steps

Exposure Meter

On a positive note the GH5S in VLOG meters correctly unlike the other GH5 siblings that are 1 stop overexposed.

You can see on the waveform monitor that setting the target at zero gives middle grey exactly on 50% on multi metering. On spot it will go at 45% which is what is expected.

Part 1 Wrap Up

From a series of quite simple tests done in a light box my expectation is that the GH5S will do ok but not sensationally in bright scenes and will do better in low light low dynamic range scenes.

In the next article I will analyse two side by side shots of the GH5S and GH5M2 in daylight.

Back in the water Sorrento Peninsula 2021

Although COVID-19 vaccinations are starting to make a difference and travel is resuming is fair to say that we are still far from where we were in 2019 and it may take some time to get back there.

This means our diving travel destinations have been changing and there is much more local diving than before. Big countries like the US have a lot of diving and Caribbean destination on their doorstep those travellers have still quite a lot to choose in comparison to others.

For Europeans, in the geographical sense, there are options for short haul travel. Those do not compare to your macro trip to South East Asia or pelagic trips to South America or Maldives or similar, however you can get some pretty good shots.

In 2020 I had my first experience in Massa Lubrense and this year I was back there.

I wrote about it last year if you are looking for more details on the logistics so in this post I will focus on photography.

Getting back into RIB diving

After 1 year of forced stop from boat diving getting back into a RIB diving with 15 liters steel tanks was a bit of a shock, certainly better than shore diving but yet not exactly streamlines especially as I decided to get a semi-dry suit. Due to stock shortages in UK I was only able to fit into a Scubapro Nova Scotia 7.5mm that has a lot of buoyancy. The suit was definitely toasty but required a lot of weight to go down as it was brand new. Temperatures range from 26 degrees at the surface to 17 at depth in certain sites so after a chilling experience last year this time I was definitely ok.

I did 2 sets of 3 days diving clocking a total of 16 dives. The dives were all close to 60 minutes (time to get back on the RIB by procedure) and depth of 33 meters. I have to say I avoid decompression dives but really this destination does require you to dive deeper than what you expect in tropical destinations.

Camera Equipment

I had the new Panasonic GH5 Mark II that fits in the housing of the Mark I and two Sea and Sea YS-D2 strobes. I took only two lenses the Canon 8-15mm fisheye with metabones smart adapter and the new (for me) Panasonic 45mm 2.8 macro.

The zoom fisheye rig looked exactly like the one in the site menu.

Wide Angle

The visibility can be an issue on the Italian coast however you can mitigate the issue with good technique and photoshop. Interestingly water is always clearer at depth where of course you lack light so strobe power is important to get a good shot.

Banco di Santa Croce is the best spot to meet large grouper and has many sea fans and also macro life, eagle rays and other things to be found.

Grouper resting between red gorgonians
Two groupers chasing

I find also very interesting the schooling fish even if this is usually not well behaved Barracuda who never spin around or a variety of sea bream

Barracudas at Scoglio Penna
Saraghi (breams) at Scoglio Penna

For me the most interesting wide angle though are the cave shots at Scoglio dell’Isca and Punta Campanella

Halloween: multiple entrances to the Isca
Zoom on the lower entrances
Schooling cardinal fish at Punta Campanella

Sunburst opportunities are abundant and due to the depth relatively easy scorpionfish or small sea fans are ideal.

Sunseeker

The performance of the Canon 8-15mm on micro four thirds is just legendary!

Close Up and Macro

Afternoon dives at Puolo but also dives in Santa Croce or Mitigliano offer lots of close up opportunities.

It was the time of testing the Panasonic 45mm 2.8 on land I had the impression it gave better rendering of the Olympus 60mm and I definitely prefer it underwater.

Male Anthias in breeding coloration
Blenny with shrimp on his head standing on a cuttlefish!
Golden Blenny
Mating nudibranches

It is not just macro a long lens gets interesting closeup of large groupers

Tompot Blenny Head On

Wrap Up

Diving in Italy delivered again. I am seriously thinking a group trip would be worth it next year based on the itinerary I sketched last year.

Dates for 2022 would be 4-11 September outside of school holidays the diving is really calm as most Italian divers are back to work and the conditions are usually superb. If you are interested leave a comment and I will come back to you with costs and planned itinerary.

Choosing the appropriate gamma for your video project

The previous post on the technical nature of V-LOG has stirred up quite a bit of unset among those people that advocate the use of it as a preferred gamma for video capture. In this post I will show some data point to help you make an informed decision based on what you are planning to shoot in your video project.

Basics of Display Gamma and Dynamic Range

First of all a bit of background on gamma curves. The standard video gamma is based on a correction factor of 0.45 as screen decode it with the reciprocal value 2.22.

Cinema gamma is historically based on a value of 1/2.6 as projectors decode with a gamma of 2.6.

Today most of our content is consumed on phones, monitors or Tv screens as well as of course cinemas but for the purpose of this post I will assume we do not have a real ambition to project in cinemas.

To give some ideas of the dynamic range of the display consider those values

Phone (HDR)9+
Computer Monitor10
Tv (1886 HDTV)11
HDR Tv13+
Projector16+
Typical Display Dynamic Range

It is important to understand how the content we produce will be consumed when we capture our source material as otherwise our video pipeline may be suboptimal.

Mobile phones and tablets are now the predominant platform to consume content and looking at the table above this means that in terms of dynamic range there is not a high requirement. In addition phones and computer monitors may also not be particularly accurate in terms of colour rendition.

HDR content, due to lack of widespread compatibility, is growing on mobile phones but remains a product for high end platforms such as HDR TVs and Projectors.

It follows that content that will be displayed at the best quality on the most common platforms has pretty limited requirements in terms of dynamic range and other qualities are perhaps more important such as sharpness, low amount of noise, colour rendition and delivery of what looks high contrast on a limited contrast medium.

A further obvious consideration is that standard rec709/sRGB video is limited to 10 stops of dynamic range in the display (contrast ratio 1000:1) while new TV sets aligned to BT.1886 can display 11 stops )(Contrast ratio 2000:1). So no matter how you acquire if you end up in rec709 the dynamic range is limited and it becomes more important to accurately capture tones and colors.

Gamma Curves for Capture

As explained capture gamma is the reciprocal of display gamma and therefore majority of cameras capture a standard video gamma (0.45) or in some cases an HDR gamma (logarithmic). I do not want this post to become a deep dive on HDR video of which I have written enough however to stay on course I want to compare traditional gamma (non linear) and log gamma.

In the following graph you see the bit codes output vs input of a standard video gamma (1/2.2) a cine gamma (1/2.6) and a log gamma (v-log).

Bit code mapping for 14 bits linear sensor data

In broad terms you can see that a video gamma produces an output of 3865 vs 16383 bits, a cinema gamma sets at 3166, while a Log gamma can take all 14 bits of data and still be within bit value 960.

It follows that to store the whole set of values read at 14 bits into a 10 bits container a standard gamma needs to do some scaling while a log gamma does not need scaling to fit into a 10 bits container. This also explains why exposure values in log are 2 stops higher than standard video for a 14 bit range, while for a 12 bit range the offset is one stop. As the meter is using a standard RGB gamma all values are rescaled back.

You notice that at no point here I have made references to dynamic range. The camera dynamic range is solely related to the maximum well capacity vs the read noise and it does not relate to the gamma curve being used, however the different compression of the gamma curve have an effect on how tones are mapped and on the perceived dynamic range.

Camera Dynamic Range vs Display Dynamic Range

The overall camera dynamic range influences what you can do with your content and if it is worthwhile to produce an HDR version or not.

If we compare the previous table of display dynamic range vs camera dynamic range and we focus on nominal values (SNR=1) and photographic (SNR=20) we can see what device we need for our purpose.

Camera TypeDRPDR (SNR=20)
Compact 12.99.8
MFT12.310.3
APSC1411.1
Full Frame1412.2
Dynamic Range by Sensor Type

We can see that if all we need to do is to output on a mobile device or a computer monitor smaller sensor are adequate, however for HDR production larger format are preferred. Obviously we can stretch SNR to lower values and this will upgrade the above table of 1 stops or so but not change our reasoning substantially.

Gamma curves vs Bit codes mapping

The various gamma curves have a different distribution of tones (bit values), in this table I compare a video gamma vs cinema a reduced 12 stops log and a full Vlog for a full frame sensor camera.

For the purpose of this comparison blacks are bit codes in the lowest 10%, Shadows are up to 18%, midtones up to 75%, highlights up to 90% and whites above. Blacks and whites do not have color information but just brightness while shadows, midtones and highlights contain respectively dark, medium and light hues.

Distribution of tones vs Gamma

A standard video gamma has over 45% of midtones, those are the colors and tones with intermediate values so produce softer tones. Shadows are just above 35% with highlights under 10% and blacks and whites around 5%.

If we look at a cinema gamma we can see that shadows are now predominant and very close to the midtones, highlights, whites and blacks are compressed.

V-LogL (12 stops DR 12 bit implementation) has the largest range in shadows, midtones are compressed around 50% compared to a video gamma, blacks are subtantially more than a video gamma, and while highlights are compressed, whites are super whites are greatly expanded.

Full VLog is dominated by whites that make 38% of the bit values, Shadows are at 32% with midtones now under 20% and highlights compressed. Blacks remain expanded.

Choosing a Gamma Curve for your Video Project

Our decision tree starts from the content which determines the device we need. Once we have a device capable of a given dynamic range we can make appropriate choices in terms of gamma curve.

Broadly speaking compact cameras and micro four thirds do not have enough device dynamic range at sufficient level of SNR to justify a high dynamic range gamma. There are some very specific exception where this may be worth it (Panasonic GH5s) but in general terms a standard MFT camera for photography should be limited to video or cinema gamma for optimal results as the dynamic range is limited and compression is not required.

If you own an MFT camera your choice is between a video gamma and a cinema gamma. Depending on the look you want to achieve you may choose one or the other. Video gamma has generally more contrast (more blacks and highlights and whites) while Cine gamma has a balance between midtones and shadows but not strong blacks and whites giving overall a softer look.

If you own a full frame or apsc camera you have more options which means you need to think more about the gamma curve to be used. HDR content requires a log curve you can then decide to use a cinema or video gamma if you do not want to output HDR or want to achieve a different look. It is important to note that log gamma have lots of bit values in whites and super whites and those do not exist in many typical scenes.

Scene vs Dynamic Range

While the current effort of camera manufacturers is to promote high dynamic range the reality is that in most cinematography situation you use devices that reduce contrast and therefore dynamic range (think about pro mist filters).

The DR of a scene can be evaluated looking at the histogram. This is of course influenced by the gamma curve so it is important to do this evaluation taking a photograph not video.

The following are example of scenes with the underlying histogram.

High Dynamic Range scene note the shape of the histogram with peaks on darks and lights
indoor scene with mostly midtones
Low contrast portrait despite the light background
Underwater landscape that does not have as much DR as you would think
Moth image predominant in midtones
Outdoor image with low dynamic range
Typical indoor party scene with flash does not have significant dynamic range
The same portrait with a cine gamma sees enhanced shadows and lighter overall image but with bright tones subdued

It may be useful to see the effect of LOG using the LUTs in photoshop on the raw data

Original image
Vlog image
Vlog + LUT back to Rec709

The example above shows that a significant number of midtones have been lost in the conversion with no DR benefit as the scene essentially lacked it.

Conclusion

For underwater video purposes as the water reduces contrast and smooths highlights I would not recommend shooting log or HDR with the exception of very specific scenarios. Likewise if I am shooting a v(ideo)log or an interview there is no requirement for extra dynamic range and log compression is not required.

Outdoor scenes especially in bright conditions, snow, are appropriate for HDR and should be shot with a log format assuming of course the luminance of the scene is not being reduced with ND filters or similar.

Events like weddings can have challenging conditions with a mix of low contrast indoor and bright outdoors with the bride typically dressed in white so in effect those can be very demanding on the equipment but you need to bear in mind that if your delivery format is just HD video the benefit of log gamma are greatly reduced and extensive work may be required to bring colours back in check, always account for the limitations of your equipment as well.

The truth about v-log

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.

Olympus vs Panasonic for Underwater Use

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.

Sorrento Peninsula 2020 UNDERWATER IMAGE MAKERS

In light of Covid-19 many long haul destinations are still closed and may potentially be for a long time so your UW photography gear may collect a good amount of dust…unless you join me for this wonderful trip, on the gulf of Naples, in the marine protected area of Punta Campanella.

Strategically located and fronted by the island of Capri Punta, Campanella offers exhilarating dives with schools of snappers, large groupers, thousands of barracudas as well as wonderful red and white gorgonians. It also offers caves, macro and amazing night dives.

Barracudas at Scoglio a Penna

More information on the website of Punta Campanella.

The area is also home to Mimmo Roscigno, a super talented local underwater photographer, who published a book on the fish life found in the area.

Jellyfish photography is possible near the coast

On top of that the area offers amazing food and views. Capri, Pompei and Positano are nearby if you fancy a trip during the degassing day.

Spaghetti with clams
Capri on the background of the RIB

Accommodation will be at Sea Breeze Residence that is 2 minutes walk from the marina and meals will be at the Paguro restaurant on the jetty, serving fresh food with local produce and fish.

Planned itinerary:

13 September Arrival in Naples. Transfer to Massa Lubrense. Light Lunch. 1530 Mandatory Check Dive. Transfer to Massa Lubrense. Check in at Sea Breeze Residence

14 – 18 September. 8.00 Double Tank dive. Lunch. 1530 Optional afternoon Dive. 20.30 Dinner.

19 September. Degassing day. Free time to explore the area (Capri, Positano, Pompei are nearby)

20 September 6.30 AM departure to Airport. 10:35 Departure to destination

Extras:

Night Dives €40

Diving Baia Archaeological Park (transfer costs only, dependant on number of participants)

Flights (average price at time of writing is under £100 excluding luggage)

Price €1,350 excluding flights includes 15 litres tanks

Due to the heavy discounts involved, a non refundable €350 deposit is required by 31st of August to block the rooms.

Covid-19 disclaimer: all operations and the hotel adopt regulation as mandated by local authorities. Room rates are based on single occupancy, double occupancy is allowed for member of the same household but will not grant any further discount on the quoted prices. In case of lockdown of the area of additional UK restriction towards Naples the trip will be postponed at no extra charge.

Other Sample Shots from the Trip

Soglio a Penna
Large resident grouper on Banco di Santa Croce
Eagle Rays are resident at Banco di Santa Croce
Stalactites in a local cave
Red coral starts at 25 meters in the area while in other site of the mediterranean is at 40 meters and deeper
The optional trip at Baia offers unique photo opportunities

Book your place here

Trip Baia di Napoli and Sorrento Peninsula

There is no doubt that until a Covid-19 vaccine is widespread our travel plans have to adjust to the new conditions. As of today 2 August 2020 most of our favourite destinations are still in the no go list and are not covered by travel insurance.

The latest list of countries and territories published by the British FCO does not include Egypt, Indonesia, Philippines and no countries in South America although it does have many Caribbean destinations.

With the situation evolving fast and the imminent prospect of tighter lock down as we go towards winter many people would not travel long haul anyway to avoid risks of quarantine or possible issues coming back to their home country. So for now, many of us will travel more locally. We have seen lots of new underwater photographs taken locally in British Waters but there is no doubt this is not out of choice and most people would rather be elsewhere.

After the postponement of my Red Sea live-aboard to 2021 I have been invited to the Italian Nauticam days in Italy in the stunning location of Napoli and Sorrento and coast. I am from the same region and all my diving training has been abroad so I am guilty of not having tried the local diving until now. If you don’t want to read the whole article the summary is that the diving is great and combined with the natural beauty of the area, the warmth of the local and the food and drink there is probably no better alternative for diving safe in Covid-19 times in Europe right now. I am sure there are equally stunning places in Liguria and some of the Sicilian or Tuscany locations however the Penisola Sorrentina is very hard to beat when you consider the other elements. Please get in touch if you want to dive the area as I am planning a trip mid September 2020.

The Diving Centre and Location

I used Punta Subaia and Punta Campanella Diving centre two long standing operations on the coast. The first is located in Bacoli north of Naples and the second is in Massa Lubrense just past Sorrento. Bacoli is Naples local beach so gets more local traffic while the other location is more touristic in nature with a good ratio of foreigners: during my stay there were English, German, French, Swiss and Dutch on the dives.

I used a 5mm wetsuit with a 3mm hooded vest and a thermal top under and was fine. Locals dive with a 7/5mm semidry suit.

Diving is done using 7.5 meters RIBs that can take up to 8 divers on a double tank or 12 on a single tank dive. Covid-19 procedures are in place and face masks are not mandatory outdoors in Italy however spacing on the RIB is challenging so you have checks and declarations to fill in. Some people wear face masks on the boat too is entirely up to you.

1 meter distance on the boat is possible

Journey time to the dive sites is 5 minutes in Baia while in Punta Campanell it can be up to half hour and the scenery is amazing as Capri is just in front of the coast and the landscape is jut breathtaking.

Under those cracks there are frequently underwater caves at shallow depth

If there is one thing that I did not like is that in the morning there was not a systematic double tank excursion so sometimes the day would finish at 6 pm with only 3 dives done. Crew are very helpful and 15 litres tanks are included at no extra so in all cases I came up because I reached the 1 hour limit still having plenty of air.

Divers getting ready to enter the water on a coastal dive

I booked a double room with single occupancy at €80 per night B&B 2 minutes walk to the dive centre. Food and drinks with wine runs at €50 or less per day and is glorious!

Spaghetti with clams will cost you €13

Underwater Photography

If you want to have an idea of the critters in the area I would recommend the book Into the Mirror from Mimmo Roscigno ISBN: 9788890966804 is only in Italian but it is a typical coffe table book the images are simply amazing.

For wide angle a good sample is on Punta Campanella Dive Center website, also look for photographers Marco Gargiulo that is local of the area. Other photographers like Franco Banfi have also been here for workshops. So there has been some fame but mostly limited to Italian speaking photographers, this is a shame as the staff speaks English and this is a photo friendly operation.

Subaia

I went for this trip with a selection of wide angle lenses, I had been told by Pietro Cremone about the underwater archeology park so I packed a rectilinear wide angle in order to avoid distortion.

Dives in Subaia are typically 1 hour long max by law at depth of 5 meters.

Dive site maps are placed underwater however you need to dive with an autorized guide

The dives have to be done with an expert guide as the mosaics are normally hidden to protect from the agents and the water.

Edoardo Ruspantini clears the debris to show the underlying Mosaic
Delfino
The Dolphin Mosaic

There are also replica statues that are good subjects, the originals are in the Napoli Museum.

Goddess of Men
Goddess of Men
Where is my hand

There are many villas and it is impossible to cover the grounds in two dives however I had planned to move to the second location so I drove two hours to Massa Lubrense on the night.

Punta Campanella

Here the diving is about fish and caves. You have a combination of close up subjects and wide angle. I took by zoom fisheye with me so I focussed on wide angle. Sea life includes plenty of Anthias and Damsel, Snappers, large groupers, eagle rays, breams, bass there is a lot of fish as the area has been a protected marine park for more than 20 years now. I was not expecting this abundance, there is also a resident shoal of Barracudas 1000+ strong specimen that is in shallow water at one of the sites. Due to limited processing power I have not yet created a 4K video however I took plenty of shots. The whole album is on flickr. I hereby include some key shots.

Medusa
Medusa
Diving Penisola Sorrentina 2020
Red Gorgonia
Ambush photo
Grouper
Behind the Mask
The Mask
Barracudas
Barracudas
Diver going through Scoglio a Penna
Caves
Eagle Ray
Eagle Ray

Wrap Up

I was frankly surprised by the sheer abundance of photo opportunities and I will be always taking my equipment whenever I go back to Italy in the summer. There are so many positives to the location:

  • Great photo opportunities
  • Well organised dive operation English speaking and photo friendly
  • Stunning location also for non divers
  • Amazing food
  • Fantastic people
  • Easy to reach from UK and other EU countries
  • Covid-19 procedures in place safe location with prime health system

I am so impressed by the location that I will be back and in fact I am planning a photo trip the week of 14 or 21 September, with the following itinerary:

  • Sunday arrival dinner with local photographers to have a taste of the area
  • Monday to Friday double tank morning dive, afternoon optional 3rd dive or sightseeing
  • Photos of the day debrief after dinner time – optional
  • Saturday no dive day local trips optional or travel independently
  • Sunday free morning transfer to airport and return

Diving cost is €400 for 5×2 tank dives to be booked in advance through me. For those we will have exclusive use of the boat optional dives in the afternoon non exclusive will be €35 per dive. Accommodation will be typically less than €600 euro for the week in single occupation and plane in the region of £100-150 depending on extras. I can help with accommodation, travel and transfers. You can also rent a car as low as £15 per day this is especially of value if planning to come with partner or family.

Please fill the contact form if interested spaces will be limited to maximum 8 for the trip. I think it will be a long time for anyone to be in tropical waters with the Covid-19 situation, this is an opportunity not to be missed until the water stays warm and enjoy one of the world very best destinations.