Category Archives: UNDERWATER VIDEO

Export Workflows for underwater (and not) video

This is post is going to focus on exporting our videos for consumption on a web platform like YouTube or Vimeo.

This is a typical workflow for video production

We want to focus in the export to publish steps for this post as things are not as straighforward as it may seem.

In general each platform has specific requirements for the uploads and has predefined encoding settings to create their version of the upload this means that is advised to feed those platforms with files that match their expectations.

The easiest way to do this is to separate the production of the master from the encodes that are needed for the various platforms.

For example in Final cut this means exporting a master file in ProRes 422 HQ in my case with GH5 10 bit material. Each camera differs and if your source material is higher or lower quality you need to adjust however the master file will be a significantly large file with mild compression and based on intermediate codecs.

So how do we produce the various encodes?

Some programs like Final Cut Pro have specific add ons in this case Compressor to tune the export however I have had poor experience with compressor and underwater video to the point I do not use it and do not recommend it. Furthermore we can separate the task of encoding from production if we insert a platform independent software in the workflow.

Today encoding happens primarily by H264 and H265 formats through a number of encoders the most popular being x264 and x265 that are free. There is a commercial right issue to use HEVC (x265 output) for streaming so a platform like YouTube uses the free VP9 codec while Vimeo uses HEVC. This does not matter to us.

So to uploade to YouTube for example we have several options:

  1. Upload the ProRes file
  2. Upload a compressed file that we optimised based on our requirements
  3. Upload a compressed file optimised for YouTube requirements

While Option 1 is technically possible we are talking about 200+ GB/hour which means endless upload time.

Option 2 may lead to unexpected results as you are not sure of the quality of YouTube output and how it matches your file so my recommendation is to follow option 3 and give the platform what they want.

YouTube Recommended Settings are on this link

YouTube recommends H264 settings as follow for SDR (standard dynamic range) Uploads

  • Progressive scan (no interlacing)
  • High Profile
  • 2 consecutive B frames
  • Closed GOP. GOP of half the frame rate.
  • CABAC
  • Variable bitrate. No bitrate limit required, although we offer recommended bitrates below for reference
  • Chroma subsampling: 4:2:0

There is no upper bitrate limit so of course you can make significantly large files however for H264 there is a point in which the quality reaches a point that you can’t see any visible differences.

Recommended video bitrates for SDR uploads

To view new 4K uploads in 4K, use a browser or device that supports VP9.

TypeVideo Bitrate, Standard Frame Rate
(24, 25, 30)
Video Bitrate, High Frame Rate
(48, 50, 60)
2160p (4k)35–45 Mbps53–68 Mbps
1440p (2k)16 Mbps24 Mbps
1080p8 Mbps12 Mbps
720p5 Mbps7.5 Mbps
480p2.5 Mbps4 Mbps
360p1 Mbps1.5 Mbps
YouTube Bitrate table

YouTube recommended settings are actually quite generous and if we perform a high quality encode we may easily be able to create smaller file however we are unsure of the logic that YouTube applies to their compression if we deviate so to be sure we will follow the recommendations.

It is very important to understand that bitrate controls the compression together with other factors however in order to get a good file we need to make sure we put some good logic in the analysis of the file itself this will greatly influence the quality of the compression process.

There is a whole book on x264 settings if you fancy a read here.

For my purposes I use handbrake and to make YouTube happy I use Variable Bit Rate with two pass and target bitrate of 45 Mbps. Together with that I have a preset that takes into account what YouTube does not like and then does a pretty solid analysis of motion as H264 is motion interpolated. This is required to avoid artefacts.

Note the long string of x264 coding commands

I have tested this extensively against the built in Final Cut Pro X YouTube Export.

Starting from the timeline and going directly into YouTube resulted in files of 88 Mb starting from a 7.06 GB ProRes 422 HQ comparable for the project. Following the guidelines and the handbrake process I ended up with 110.1 MB which is a 24% increase.

I have also exported to H264 in FCPX this gave me a 45.8 Mbps file however when I checked on YouTube their file it was still smaller than my manually generated file of 12%. I have used 4K video downloader to retrieve file sizes.

Same source file different encodes different results in YouTube

For HDR files there are higher allowed bitrates and considerations on colour space and color depth but is essentially the same story and I have developed HandBrake presets for that too.

When I have to produce an export for my own use I choose H265 and usually a 16 Mbps bitrate which is what Netflix maxes at. Using Quality at RF=22 produces around 20 Mbps files which is amazing considering the starting point of 400 Mbps for GH5 AVCI files. YouTube own files range between 10 and 20 Mbps to give you an idea once compressed in VP9. I cannot see any difference between my 16 Mbps and 20 Mbps files so I have decided to stay with the same settings of Netflix if it works for them will work for me.

There is also a YouTube video to explain in detail what I just said and some comparative videos here

For all my YouTube and Blog subscribers (need to be both) please fill the form and I will send you my 3 handbrake presets.

Edit following some facebook discussions: if you want to upload HD you have better results if you make the file 4K. According to my tests this is not true. Using x264 and uploading an HD file produces same or better results than the HD clip YouTube created out of the same source using a 4K upload. I would be vary about what you read on the internet unless you know exactly how clips are produced. 90% of the issue is poor quality encoding before it even gets to YouTube!

Colour Correction in underwater video

This is my last instalment of the getting the right colour series.

The first read is the explanation of recording settings

https://interceptor121.com/2018/08/13/panasonic-gh5-demystifying-movie-recording-settings/

This post has been quite popular as it applies generally to the GH5 not just for underwater work.

The second article is about getting the best colours

https://interceptor121.com/2019/08/03/getting-the-best-colors-in-your-underwater-video-with-the-panasonic-gh5/

And then of course the issue of white balance

https://interceptor121.com/2019/09/24/the-importance-of-underwater-white-balance-with-the-panasonic-gh5/

Am not getting into ambient light filters but there are articles on that too.

Now I wanted to discuss editing as I see many posts on line that are plain incorrect. As it is true for photos you don’t edit just looking at an histogram. The histogram is a representation of the average of the image and this is not the right approach to create strong images or videos.

You need to know how the tools work in order to do the appropriate exposure corrections and colour corrections but it is down to you to decide the look you want to achieve.

I like my imaging video or still to be strong with deep blue and generally dark that is the way I go about it and is my look however the tools can be used to have the look you prefer for your materials.

In this YouTube tutorial I explain how to edit and grade footage produced buy the camera and turn it into something I enjoy watching time and time again.

I called this clip Underwater Video Colour Correction Made Easy as it is not difficult to obtain pleasing colours if you followed all the steps.

A few notes just to anticipate possible questions

  1. Why are you not looking to have the Luma or the RGB parades at 50% of the scale?

50% of the IRE scale is for neutral grey 18% I do not want my footage to look washed out which is what happens if you aim at 50%.

2. Is it important to execute the steps in sequence?

Yes. Camera LUT should be applied before grading as they normalise the gamma curve. In terms of correction steps setting the correct white balance has an influence on the RGB curves and therefore needs to be done before further grading is carried out.

3. Why don’t you correct the overall saturation?

Most of the highlights and shadows are in the light grey or dark grey areas. Saturating those can lead to clipping or noise.

4. Is there a difference between using corrections like Vibrancy instead of just saturation?

Yes saturation shifts equally the colours towards higher intensity vibrancy tends to stretch the colours in both direction.

5. Can you avoid an effect LUT and just get the look you want with other tools?

Yes this is entirely down to personal preference.

6. My footage straight from camera does not look like yours and I want it to look good straight away.

That is again down to personal preference however if you crush the blacks or clip the highlights or introduce a hue by clipping one of the RGB channels this can no longer be remediated.

I hope you find this useful wishing all my followers a Merry Xmas and Happy 2020.

Matching Filters Techniques

The issue is that the Ambient light filters are set for a certain depth and water conditions and does not work well outside that range. While the idea of white balancing the scene and getting colour to penetrate deep into the frame is great the implementation is hard.

Thinking about Keldan we have a 6 meters version and a 12 meters version as listed on their website. The 6 meters version works well between 4 and 12 meters and the other between 10 and 18. At the same time the Spectrum filter for the lens works down to max 15 meters and really performs better shallower than 12 meters.

With that in mind it follows that if you plan to use the spectrum filter -2 you are probably getting the 6 meters ambient filters. So what happens if you go deeper than 12 meters? The ambient light filter is not aligned to the water ambient light and the lights start to look warm this is not such a bad thing but can get bad at times.

You can of course white balance the frame with the lights however this becomes somewhat inconvenient so I wanted to come out with a different technique. In a previous post I have described how to match a lens filter to a light/strobe filter. Instead of matching the light filter to the ambient light I match the filters on land between each other in daylight conditions to obtain a combination that is as much as possible neutral. I have done this for URPRO, Magic Filter and Keldan Spectrum filter and worked out the filter that when combines give a neutral tone.

Magic filter combined with 2 stops cyan filter giving almost no cast

This tone tends to emulate the depth where the filter has the best color rendition. So in case of Keldan this is around 4 meters and so is Magic with URPRO going deeper around 6-9 meters.

The idea is that you can use the filter without lights for landscape shots and when you put the lights into the mix you can almost shoot in auto white balance or set the white balance to the depth the two were matching. I wanted to try this theory in real life so I did 3 different days of diving testing the combination I had identified the results are in this video.

The theory of matching filters worked and the filter more or less performed all as expected. I did have some additional challenges that I had not foreseen.

Filter Performance

The specific performance of a filter is dependant on the camera color science. I have had great results with URPRO combined with Sony cameras but with Panasonic I always had an orange cast in the clips.

Even this time the same issue is confirmed with the URPRO producing this annoying cast that is hard if not impossible to remove also in post.

The Magic filter and the Spectrum filter performed very close, with magic giving a more saturated and baked in image with Keldan maintaining a higher tone accuracy. This is the result of the design of the filters: the Magic filter has been designed to take outstanding picture better than life, the Spectrum filter has been designed using tools to give accurate color rendition. What it means is that the magic images look good even in the LCD while Keldan are a bit dim but can be helped in post.

Looking at the clip in the first 3 and half minutes you can’t tell apart Magic and Spectrum down to 9 meters, with the URPRO giving consistent orange cast.

Going a bit deeper I realised you also need a scenario where you are swimming closer to a reef and want to bring some lights in the frame because you are outside the best working range of the filter. In order to avoid excessive gap when approaching the reef I had stored white balance readings at 6 9 12 15 meters so when I had a scene with mixed light instead of balancing for say 15 meters and then having an issue with the light I used the 9 meters setting so the image is dim when you are far and gets colorful as you approach which is somehow expected in underwater video.

The section at 15 meters are particularly interesting

You can see that URPRO gets better with depth but also how at 5:46 you see a fairly dim reef at 5:52 I switch on the lights and the difference is apparent.

At 6:20 the approach with Keldan was directly with the lights the footage still gives an idea of depth however the colours are there and the background water looks really blu as I had white balance set for 9 meters.

Key Takeaways

All filters produced acceptable results however I would not recommend URPRO for the Panasonic GH5 and settle for the Magic Filter or the Spectrum filter. Today the spectrum is the only wet filter for the Nauticam WWL-1 but I am waiting for some prototypes from Peter Rowlands for the magic. I would recommend both the magic and the spectrum and the choice really depends on preference. If you want a ready look with the least retouching the magic filter is definitely the way to go as it produces excellent ready to use clips that look good immediately in the LCD.

The Keldan Spectrum filter has a more desaturated look and requires more work in post but has the benefit of a more accurate image.

I think this experiment has proved to work and I will use this method again in the future. This method is also potentially available using the keldan or other ambient light using a tone that closely matches the lens filter.

 

Filter Poll

Choosing the Appropriate Frame Rate for Your Underwater Video Project

I think the subject of frame rates for underwater video is filled with a level of non-sense second to none. Part of this is GoPro generated, the GoPro being an action cam started proposing higher frame rates as standard and this triggered a chain reaction where every camera manufacturer that is also in the video space has added double frame rate options to the in codec camera.

This post that no doubt will be controversial will try to demistify the settings and eliminate some fundamental misconception that seem to populate underwater videography.

The history of frame rates

The most common frame rates used today include:

  • 24p – used in the film industry
  • 25p – used in the PAL broadcasting system countries
  • 30p – used in the NTCS broadcasting system countries

PAL (Phase Alternating Line) and NTSC (National Televion System Committee) are broadcasting color systems.

NTSC covers US South America and a number of Asian countries while PAL covers pretty much the rest of the world. This post does not want to in the details of which system is better as those systems are legacy of interlaced television and Cathodic Ray Tubes and therefore are for most something we have to put up with.

Today most of the video produced is consumed online and therefore broadcasting standards are only important if you produce something that will go on Tv or if your footage includes artificial lighting that is connected to the power grid – so LED does not matter here.

So if movies are shot in 24p and this is not changing any time tomorrow why do those systems exist? Clearly if 24p was not adequate this would have changed time ago and except some experiments like ‘The Hobbit’ 24p is totally fine for today use even if this is a legacy of the past.

The human eye has a reaction time of around 25 ms and therefore is not actually able to detect a moving object in the frame at frame rates higher than 40 frames per second, it will however detect if the whole room moves around you like in a shoot out video-game. Our brain does a brilliant job of making up what is missing and can’t really tell any difference between 24/25/30p in normal circumstances. So why do those exist?

The issue has to do with the frequency of the power grid and the first Tv based on Cathodic Ray Tube. As the power of the grid runs at alternate current with a frequency of 60 Hz in the US when you try to watch a movie on Tv that has been shot at 24p this has judder. The reason is that the system works at 60 cycles per second and in order to fit your 24 frames per second there is a technique called Telecine. To make it short artificial fields are added each 4 fields so that this comes up to 60 per second however this looks poor and creates judder.

In the PAL system the grid runs at 50 Hz and therefore 24p movies are accelerated to 25p and this the reason the durations are shorter. The increased pitch in the audio is not noticeable.

Clearly whey you shoot in a television studio with a lot of grid powered lights you need to make sure you don’t have any flicker and this is the reason for the existence of 25p and 30p video frame rates. Your brain can’t tell the difference between 24p/25p/30p but can very easily notice judder and this has to be avoided at all costs.

When using a computer display or a modern LCD or LED Tv you can display any frame rates you want without issues therefore unless you are shooting under grid power artificial lights you do not have to stick to any broadcasting system.

180 Degrees Angle Rule

The name is also coming from a legacy however this rule establishes that once you have set the frame rate your shutter speed has to be double of that. As there is no 1/48 shutter 24/25p are shot at 1/50s and 30p is shot at 1/60s this makes sure also everything stays consistent with possible flicker of grid powered lights.

The 180 degrees angle rule gives each frame an amount of motion blur that is similar to those experienced by our eyes.

It is well explained on the Red website here. If you shoot slower than this rule the frames look blurry if you choose a faster shutter speed you eliminate motion blur so in general everybody follows this and it works perfectly fine.

Double Frame Rates

50p for PAL and 60p for NTSC are double frame rates that are not part of any commercial broadcasting and today are only supported officially for online content.

As discussed previously our reaction time is not able to detect more than 40 frames per second anyway so why bother shooting 50 or 60 frames per second?

There is a common misconception that if you have a lot of action in the frame then you should increase the frame rate but then why when you are watching any movies you don’t feel there is any issue there even if you are watching Iron Man or some sci-fi movie?

That is because those features are shot well with use of a lot of equipment that makes the footage rock steady, the professionals that do it follow all the rules and this looks great.

So the key reason to use 50p or 60p has to do with not following those rules and not being that great of shooting things in a somehow unconventional manner.

For example you hold the camera while you are moving for example a dashboard cam, or you hold the camera while running. In this case the amount of changes in the frame is substantial as you are moving not because things around you are moving. So if you were still in a fixed point it will not feel like there is a lot of movement but if you start driving your car around there is a lot of movement in the frame.

This brings the second issue with frame rates which is panning again I will refer to Red for panning speed explanation.

So if you increase the frame rate from 30 to 60 fps you can double your panning speed without feeling sick.

Underwater Video Considerations

Now that we have covered all basics we need to take into account the reality of underwater videography. Our key facts are:

  • No panning. Usually except some cases the operator is moving with the aid of fins. Panning would require you to be in a fixed point something you can only do for example in a shark dive in the Bahamas
  • No grid powered lights – at least for underwater scenes. So unless you include shots with mains powered lights you do not have to stick to a set frame rate
  • Lack of light and colour – you need all available light you can use
  • Natural stabilisation – as you are in a water medium your rig if of reasonable size is floating in a fluid and is more stable

The last variable is the amount of action in the scene and the need of slow motions – if required. The majority of underwater scenes are pretty smooth only in some cases, sardine runs, sea lions in a bait ball there really is a lot of motion and in most cases you can increase the shutter speed without the need to double the frame rate.

When I see video shot at 50/60p and played back at half speed for the entire clip is really terrible and you loose the feeling of being in the water so this is something to be avoided at all costs and it looks plain ugly.

Furthermore you are effectively halving the bit rate of your video and to add more usually the higher frame rate of your camera is not better than the normal frame rate of your camera and you can add more frames in post if you wanted to have a more fluid look or perform a slow motion.

I have a Panasonic GH5 and have the luxury of normal frame rates, double frame rates and even a VFR option specifically for slow motions.

I analysed the clips produced by the camera using ffprobe to see how the frames are done and how big they are and discovered a few things:

  1. The 50/60p recording options at 150 Mbps have a very long GOP essentially a full frame is recorded every 24 frames while the 100 Mbps 25/30p records a full frame every 12 frames. So the double frame rate has more frames but is NOT better at managing fast moving scenes and changes in the frame.
  2. The VFR option allows you to set a higher frame rate and then slows down recording to the frame rate of choice. For some reason the 24p format has more options than all the others and the 25p does not even have a 50% option. As the footage is recorded at 100 Mbps the VFR footage at half speed conformed to 30p is higher quality than 60p slowed down to 30p (100 Mbps vs 150/2=75 Mbps) in terms of key frames and ability to predict motion this is better as it has double the amount of key frames per second see this explanation with details of each frame look for the I frames.
  3. The AVCI all intra option has actually only I frames and it will have 24/25/30 of them per second and therefore it is the best option to detect fast movement and changes in the frame. If you need to slow this down this still has 12 key frames per second so other frames can easily be interpolated.
  4. Slow motion – as the image will be on the screen for longer and it is slowed down you need to increase the shutter speed or it will look blurry. So if you intend to take a slow mo you need to make that decision at time of your shot and go for a 90 or 45 degree angle. This remains through if you use VFR or if you slow down AVCI clips in post
  5. If you decided AVCI is not for your the ProRes choice is pretty much identical and again you do not need to shoot 50/60p unless you have specific situations. In general AVCI is equal or better than ProRes so the whole point of getting a recorder is highly questionable but that is another story.

For academic purposes I have compared the 3 different ways Final Cut Pro X does slow down. To my surprise the best method is the ‘Normal Quality’ which also makes sense as there are many full frames.

Now it is interesting to compare my slow motion that is not ideal as I did not increase the shutter speed as the quality of AVCI is high the footage looks totally fine slowed down

Various slow motion technique in FCPX with 1/50s shutter

Looking at other people example you get exactly the wrong impression you take a shot without increasing the shutter speed and then slow it down. The reason why 60p looks better is for the shutter speed not for the image quality itself it is also completely unneeded to slow down a whale shark as it glides through the water.

The kind of guidance you get

So taking this kind of guidance blindfolded is not a good idea.

Key Take Aways

  • Unless you shoot using main grid powered lights you can choose any frame rate you want 24/25/30 fps.
  • Shutter speed is important because it can give a motion blur or freeze motion in case of a slow motion clip
  • You need to choose what scenes are suitable for slow motion at time of capture
  • Slowing down systematically your footage is unnatural and looks fake
  • Using formats like AVCI or ProRes gives you better option for slow down than 50/60 fps implementation with very long GOP
  • VFR options can be very useful for creating purposes although they have limitations (fixed focus)

How do I shoot?

I live in a PAL system country however I find always limitations with the 25 fps options in camera. The GH5 VFR example is not the only one. All my clips are shot 24 fps 1/50s, I do not use slow motion enough and if I did I would probably keep using AVCI and increase the shutter speed depending on the effect I want to give to the scene, this is also the most natural and easier way to shoot underwater as you do not have to continuously change format. Having all intra frames gives me all the creativity I need also for speed ramps that are much more exciting than plain slow motion see this example.

interceptor121’s cut – Nauticam n85 Panasonic Olympus and BMPCC port chart

I thought of adding a little stickie post of what I use for my Panasonic GH5 in terms of lenses ports so I made some edits on the official port chart v7.19 please find the google drive link here

There is an addition that I will cover in future posts and relates to using the Canon 8-15 mm Fisheye zoom lens on the GH5 body using a Smartbones Smart Adapter or Vitrox EF-M1.

I have already written about choice of Macro lenses fisheye and wet lenses for video and wide and for macro video.

My latest post is on rectilinear wide angle lenses that is a tricky subject for most.

The importance of Underwater white balance with the Panasonic gh5

One of the key steps in order to get the best underwater colours in your video is to perform a custom white balance.

This is true on land and on water because auto white balance only works in a specified range of color temperatures.

Panasonic GH5 advanced user manual

For our GH5 the range where auto works goes is approximately 3200-7500K. When the camera is working outside this range you get a colour cast. Let’s see with some examples:

Grey card Auto White Balance 8mm
Grey card Custom White Balance 8mm

In the example above I am taking a picture of a white balance reference card under warm lights that have a colour temperature of 2700K.

As you can see the auto white balance fails resulting in a yellowish tinge, while the shots taken after the custom white balance is accurate.

In terms of white balance card I use the Whibal G7 Studio 3.5″x6″ (8.9×15.2 cm). I found this card to work well underwater and I use it with a lanyard attached to a clip that I hook on my BCD D rings.

More info on the whibal here

It is possible to buy a larger card such as the reference that is 7.5″x10″ however this is cumbersome and I found the Studio version to work well with the Panasonic GH5 as it only uses the central part of the frame for white balance.

Custom white balance with the 8mm fisheye

Going back to our GH5 instruction manual you can also see that the camera white balance is limited to 10,000K which is the colour of blue sky.

Underwater due to light absorption at longer wavelengths red and orange disappear at depth and blue tends to scatter over suspended particles. So the colour temperature of water tends to be higher than 10,000K and also the blue is somewhat washed out by scattering.

This is the reason filters are essential because reduce the amount of blue or to say better cyan and bring the camera into a range where custom white balance works again.

I have already posted a whole range of observations on filters in a previous post so am not repeating here.

With the right filter for the water colour I dive in and with the appropriate white balance card you can get some pretty decent results with custom white balance.

To help the colour accuracy I have experimented with the Leeming Luts and I want to thank Paul Leeming for answering my obscure questions. Obviously you do not have to use the LUTs and you can design them yourself however I found that using the Cinelike D LUT I have a very good starting point for colour correction.

The starting point is a CineLike D profile with saturation, noise reduction and sharpness set to -5 all other settings to default as suggested by Paul, there is no need to lower the contrast as CineLike D is already a flat curve.

*Noise and sharpness have actually nothing to do with grading but are set to -5 as the GH5 applies sharpening and noise reduction even at -5 setting. Sharpening has generally a negative effect all around while noise reduction if required is better performed in the editor.

Looking at imaging resource tests of the GH5 we can appreciate that the camera colours are oversaturated by default.

the GH5 has around 113% over saturated colours

The GH5 tends to push deep colour and wash out cyan and yellow. This becomes apparent when we look at a white balanced clip uncorrected.

White balanced clip in final cut pro you can see how the water column is washed out whilst red and other dark colours are accurate

The Leeming Lut helps rebalancing the camera distorted colours and when you apply the camera LUT, provided you have followed the exposure instructions and applied the profile as described, the improvement is immediate.

The previous clip now with the CineLike D Leeming LUT applied

From here onwards it is possible to perform a better grading and work to improve the footage further.

For the whole read please look at Leeming Lut website

One other thing that I believe it is interesting is that while generally for ambient light or balanced light shots I do not actually trust the camera exposure and go -1/3 to -2/3 for close up shots exposing to the right greatly helps highlights recovery

In the two frames you can see the difference the LUT brings restoring the correct balance to the head of the turtle.

Turte detail the highlights appear blown out
Turtle detail with Leeming Lut applied

To be clear the turtle detail has been white balanced in water on the whibal card while using a Keldan Spectrum filter -2, then in fcpx automatic balancing is applied. The LUT brings out a better dynamic range from the same frames.

Obviously you are free to avoid lens filters and LUTs and to some extent it is possible to get similar results however the quality I obtain using automatic settings I believe is quite impressive.

I found myself most times correcting my own wrong exposures or wanting to increase contrast in scene where I had little however this only happens in sever circumstances where white balance and filters are at the limits.

Conclusion

There are many paths to get the right colours for your GH5 underwater videos in my opinion there are four essential ingredients to make your life easier and give your footage a jump start:

  • Take a custom white balance using a professional grade white balance card
  • Set the right picture profile and exposure when shooting
  • (Recommended) Use appropriate filters for the water conditions
  • Apply the appropriate LUT to eliminate the errors in the GH5 colour rendering in post processing

With the following settings producing a video like this is very simple and all your efforts are in the actual cutting of the clip.

Short clip that applies this blog tips

Please note some of the scenes that look off are shot beyond the working conditions of filters and white balance at around 25 meters…

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

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.

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

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

RED SEA 2020 UNDERWATER IMAGE MAKERS LIVEABOARD

Diving for images or video can be frustrating at times. I find this less so for macro and super macro where you are resort based and you can hire a guide with super sharp eyes that will help you find the right subjects. For wide angle it is a totally different story. Land based may preclude the best access to certain destinations whilst if you are on a liveaboard with divers there is a conflict of interest. The boat will typically run a fixed itinerary cruise and the result is that you will visit many times so more memorable than others and typically just once. The single dive you do may not be at the right time of the day and the ambient light may not be the best for what you trying to do.

I am self taught and I like to read books and experiment myself however some years ago I was invited by Nauticam to a Red Sea workshop with Alex Mustard.

I wrote some articles at the time you can find them all if you click this link https://interceptor121.com/?s=workshop

What I really liked about that workshop was the ability to steer the boat to the right sites, to be able to dive at the right time of the day and also to repeat dives on the best sites and omit the areas that were not promising. For me this had great value on its own.

Of course Dr Alex Mustard tuition was also superb however I have now done this workshop 3 times and I believe that element has become less interesting. I also happened to work in Sharm El Sheikh as resident instructor at the Marriot Hotel so all dive sites were already known to me as a diver at least.

On those workshops I found very useful the fact that you could see the work of others and learn from the group, I also like the fact that there was no competition so everybody was encouraged to share.

Needless to say that after years of diving the same sites I still find the Northern Wreck and reefs of the Red Sea one of the best imaging destination in the world so I thought how do I have the same experience without the workshop part and the related high costs – it costs almost double a standard diving trip to book Alex workshop and they are fully booked almost immediately.

A further issue that has occurred in time is that there are no flights to Sharm El Sheikh from UK and now majority of boats live from Hurghada. This seriously limits the workshop as you have a lot more navigation.

So my ideal requirements for such a trip would be:

  1. Boat to live from Sharm El Sheikh not Hurghada. I rather have indirect flights and burn land time vs consuming cruise time in transfers
  2. Need to be able to have full control of the itinerary
  3. Dive as a photographer with a loose buddy concept
  4. Have a good boat and logistics
  5. Have small number of people in the water – I think 20 is too much so I have set my target to 8 min 12 max

I reconnected with my old network and after looking around I have found a boat and a company that can help with this.

King Snefro is the only liveaboard fleet currently departing from Sharm El Sheikh and the boat of choice is the Snefro Pearl

Cruise Dates: 1-8 August 2020

Price: €1250 per Pax in twin cabin includes:

  • 32% Nitrox
  • Airport transfers
  • 12 Liter tanks
  • 3 meals, snacks and soft drinks, tea and coffee
  • Special imaging orientated dive briefing to make the most of the sites
  • Group image debrief – optional participation
  • Arrival on Saturday 1st August – check in commences at 1800
  • Check out Saturday 8th August – 1200 latest
  • For those whose flight leaves much later possibility of a stop gap in a beach resort before final departure

You need to be a PADI Advanced Open Water Diver or equivalent and 30 logged dives are required for this safari. All dives, especially some more demanding wreck dives, are subject to diver’s qualification and experience. 

EAN or other Nitrox certification required if not training will be provided on the boat at a charge.

Extra Hotel arrangements if you are coming the day before or leaving the day after

per night per person

*Club El Faraana Reef*​ –  www.faraanareef.com

Halfboard  in Single Room = 50 € per night per person
 Soft All in per in Single room = 60 € per night per person

Halfboard  in Double  Room = 35 € per night per person
Soft All in Double room = 45 € per night per person

Halfboard  in Triple  Room = 30 € per night per person
Soft All in Triple room = 40 € per night per person

Service Charge & taxes included, Transfer Airport to Hotel/ Hotel to Airport is included
(Check in starts from 14:00 H, Check out till 12:00 H,  in combination with safari booking early check in or late check out will be arranged free of charge) 

On to the dive sites:

Wrecks of Abu Nuhas

Giannis D

Gianni's D classic shot
Giannis D Classic Shot

Carnatic

Encircled
Silversides and diver in the Carnatic

Chrisoula K

Chrisoula K Bow
Bow of Chrisoula K

The Tugboat

Stay Away from my Eggs
Tiger cardinal fish with eggs

The Thistlegorm

Motorbike in Hold 2
bike on hold 2

Ras Za’tar (Optional site for sunbursts)

Sunburst
Suburst on Ras Za-tar

Jackfish Alley – Optional site for caves

1st Cave@Jackfish Alley
Cave 2 Jackfish alley

Ras Mohammed where at that time of the year you can have various shoals of fish

Bohar Snappers

Sunburst  Snap
Snapper Sunburst

Barracudas

Arrows
Arrows

Batfish

Schooling Batfish on Reef
Bats

Surgeonfish

Toilet Flush
Toilet flush

Instead of night dives we will do snorkelling session for split shots or sunset dives

Sunset Neat
Sunset on Ras Katy

I will be glad to help with ideas for the sites or the shots to take however this is not for beginners so if you don’t know even how to work out your camera works maybe it is not for you. The trip is open to photographers and vdeographers I will shoot both and will provide assistance as required. Below little sample of the video opportunity in Shark Reef

If you are interested in this trip deposit of 25% is due by September 23 2019 full payment by 25 January 2020.

Please use the form to express your interest. In case the cruise it is sold out I will operate strictly a first come first serve basis at time of writing there are five space left so hurry up. In case of cancellation I will also run a wait list. Please inquiry for any other details as well

NAUTICAM WWL-1:THE BEST WIDE ANGLE LENS FOR UNDERWATER VIDEO (ON THE GH5 AND OTHER MICRO FOUR THIRDS)

It has been almost 4 years since my first review of the Nauticam WWL-1 wet wide angle lens and a few accessories later this lens is definitely my all time favourite for underwater video with my GH5.

I do not want to repeat myself and beat to death the topic of sharpness in corners I would rather recap on the other benefits of this lens that really make it unique for underwater video. Obviously this lens is very valid also for still images because of the ability to zoom through but this is not the focus of this post.

So let’s have a look at the three killer features of this lens that make it really special

Field of view

The WWL-1 once combined with the Panasonic 14-42mm MKII (the best lens to combine with the WWL-1 in my view) offers a field of view of 130 degrees diagonal. But what does that really mean?

First the WWL-1 does not compare with a rectilinear lens in fact it is almost a fisheye lens as we can see from those shots of a pool wall.

WWL-1 at 14mm wide end

The barrel distortion is evident correcting the image in lightroom gives an idea although not 100% correct of what is the real field of view of the lens.

WWl-1 at 14mm with distortion correction at 100

What is interesting to see is that the WWL-1 like a fisheye lens offers a much wider diagonal field of view than on the other dimensions.

I have compared the WWL-1 with other rectilinear lenses and with the 8mm fisheye.








Horizontal  25 50 100 200 FOV Linear Ratio to FE
7-14mm@7 62 124 248 496 102 57%
8-18mm@8 54 108 216 432 94 50%
12-60mm@12 36 72 144 288 72 33%
WWL-1 61 122 244 488 102 56%
Fisheye 8mm 109 218 436 872 130 100%







Vertical 25 50 100 200 FOV
7-14mm@7 46 92 184 368 86 84%
8-18mm@8 41 82 164 328 78 75%
12-60mm@12 27 54 108 216 57 49%
WWL-1 39 78 156 312 75 71%
Fisheye 8mm 55 110 220 440 96 100%







Diagonal 25 50 100 200 FOV
7-14mm@7 77 154 308 616 114 13%
8-18mm@8 68 136 272 544 107 12%
12-60mm@12 45 90 180 360 84 8%
WWL-1 107 214 428 856 130 18%
Fisheye 8mm 583 1166 2332 4664 170 100%

The table I have prepared uses the equisolid equation for a fisheye lens to map the WWL-1 I have verified the values and I can confirm the WWL-1 is somehow equivalent to 10.06mm fisheye lens.

There are two things that are worth noting, the first is that on the horizontal and vertical axis the WWL-1 is not wider than the Panasonic 7-14mm at 7mm. The other consideration is that with the WWL-1 the 4:3 format frame starts to become a classic 3:2 as the ration width/height is 1.56.

When we work in video at 16:9 we crop out most of the diagonal part leaving the rest of the field of view intact this means that in video mode the lens is much more rectilinear and the barrel distortion more contained.

14mm WWL-1 cropped at 16:9

If we look at a frame at 25mm we can see that at 4:3 the level of distortion is reduced but still present.

WWL-1@25mm

.The corrected frame shows the residual distortion.

WWL-1@25mm corrected
WWL-1@25mm 16:9 crop

The level of residual distortion in video mode is pretty negligible at 25mm. At 35mm even in 4:3 mode the WWL-1 is practically straight.

The benefit of the distortion of the WWL-1 is such that if you are shooting large sharks for example the barrel distortion makes those sharks look large in the centre of the frame and when they go out of the frame you don’t have the pull effect of a classic rectilinear lens behind a dome. At the same time if you need to shoot some divers or lines that are straight you can zoom in and still cover a pretty wide field of view.

Stabilization

The other benefit of the WWL-1 is that allows you to use lenses that are stabilised, today any lens at the 7-8mm range on micro four third has no stabilisation which means you need to use the in body stabiliser if available with your camera. For the GH5 this means that choosing a lens like the 14-42 MkII gives you access to Dual IS combining body and lens stabiliser and IS lock that really is useful when finning around. I just want to make sure that I am clear I am talking of this lens

https://www.panasonic.com/uk/consumer/cameras-camcorders/lumix-camera-lenses/lumix-g-lenses/h-fs1442ae.html

The Panasonic 14-42PZ power zoom is NOT compatible with dual IS so if you use this lens you either have in body or lens stabiliser not both. Obviously if you have a camera without stabilisation like the GH5s or the BMPCC 4K all of this is less relevant but still you can have some stabilisation instead of nothing.

I have not shot a comparative Dual IS vs Lens IS vs nothing in the pool but I am planning to do that soon. I can only say once you have dual IS with IS lock you don’t want to go back.

Filters

The final killer feature of the WWL-1 is that it gives you access to the Keldan Spectrum filters review here http://wetpixel.com/articles/review-keldan-spectrum-and-ambient-filters-by-massimo-franzese

Personally I think that any dive down to 18 meters in tropical or subtropical water will benefit from a filter but I also believe that conditions may change and in some cases you want to take the filter off. Now most of the rectilinear lenses for the GH5 do not even take a filter but also consider that once you fit one in dome port you are stuck with it for the dive. With the WWL-1 and the Keldan filter if you feel there is too little light and you want to get rid of the filter you can.

Keldan filter in action