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Sony a7s II underwater use -- All parameters

picture profile white balance sony a7s II grading color correction 4K UHD

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#41 Ammar

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Posted 03 September 2016 - 11:22 PM

George. Sony A7RII does not have S-Log3 like the A7SII. I would have gone with the S-Log3 profile without a doubt if my cam has it as it captures more dynamic range and much better for grading as the reviews suggest.



#42 dreifish

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Posted 05 September 2016 - 12:28 AM

Ammar, I think you have to be very careful about SLOG2/SLOG3 shooting underwater on the A7 cameras. Because SLOG is NOT raw. What slog is doing is trying to squeeze in a broader luminance/chrominance range in the same 8-bit 4:2:0 100mb/s video container, unlike RAW photos, where a JPEG is 8-bit 4:2:2 compressed image and the raw is 14-bit 4:4:4 (kinda, it's actually the luminance level for each sensor pixel, which you debayer to color information when you process the raw).

 

There's a couple of important implications to this. First, SLOG2 has a baked-in white balance, just like a JPEG, and unlike a RAW. So whether you shoot with no picture profile or SLOG, you still have to get the white balance right at the time of acquisition. You will have much less flexibility to correct it later than you would with a RAW photo file, or even with a JPEG file (since JPEG is 4:2:2, it records twice as much color information as the video, which is 4:2:0). 

 

Second, because SLOG is trying to squeeze in a much larger color and luminance range into the same container, you end up using fewer bits to represent luminance/color variation. Which, in practice, means you have LESS room for fine color corrections in post with SLOG footage than with no picture profile footage. Plus, the colors are just off. Now, I'm not a great colorist by any means, but in my experiments shooting the same scene with no picture profile and SLOG underwater, the no picture profile image looks much better both right out of camera and after post-processing -- better saturation, better color accuracy, etc. Yes, you have to be careful to expose correctly for the main parts of the image and you will get some parts that are blown out, but the properly exposed parts will look good -- if you get the white balance right. With SLOG, none of it looks right, and adjusting it in post still doesn't produce an image as nice as the no picture profile image.

 

I'll try to post a few examples of footage I've shot recently with ambient light (shallow) in UAWB mode and with artificial light (a bit deeper) later this week. After using this camera on 100+ dives, including 50+ video-focused dives, I'd say it IS possible to get very nice footage from it. But you have to get it in camera as much as possible, relying on post-processing for minor adjustments (minor levels and contrast, primarily, rather than color shifts). 

 

Since I got the Gates GT14 lights, I've also tried to do some shooting with lights in UAWB mode -- the results are interesting. Generally, setting custom white balance to the lights (5200K for me) is better if you're shooting a scene where the lights are the primary source of illumination (subject <0.3m away, depth 20m+). However, if shooting wide angle in shallower depths or where the subject extends beyond 0.5m away, you actually can get decent color shooting in UAWB mode with the lights on. Of course, just like if you were shooting with a red filter and lights, if your subject gets too close to the lights, the red is going to be emphasized a bit too much. So Sony's UAWB mode is not smart enough to dial the red boost down if there's a strong source of warm light in the scene. But for scenes where the lights provide a more limited fill, the overall balance is actually not bad.

 

When I get a chance (and get the right filters), I'm going to try to put some blue gels on the lights to cool them down and see what results I can get shooting with gelled lights and UAWB mode. I'm expecting this might actually produce the most pleasing images in the 10-20m range, or even below 20m. Above 5 meters, especially with clear water and a sunny day, the UAWB mode works really, really well with or without a filter. 



#43 Ammar

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Posted 05 September 2016 - 01:01 AM

dreifish, truly appreciate the info. Most valuable.

 

Actually I thought that Slog was like shooting RAW and wasn't aware of the technicality you stated thankfully. So, there is no profile in the cam to shoot video in RAW like mode? Do you recommend shooting video in standard mode based on your experience?

 

As I said I'm totally new to the video profiles thing thus still exploring how to get the best out of it.



#44 bubffm

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Posted 05 September 2016 - 05:17 AM

If I may just add one more argument to that great summary from dreifish for not shooting SLOG underwater:  Due to its curve SLOG is not really ideal for low light situations and you are much more likely to get blocking and noise.  

 

This is due to the fact that in SLOG you got lots of dynamic range at the highlights, but this comes at the expense of not so much dynamic range in the lowlights / midrange. However, as protecting highlights is not the key issue for underwater filming I would use "normal" or Cinegamma Settings (PP5 or 6 on the A7SII if I recall correctly) instead.

 

If you want to dig deeper on the subject of Sony's picture profiles and gamma curves, there is some excellent write up by Alister Chapman on his blog http://www.xdcam-user.com.

 

bubffm



#45 dreifish

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Posted 05 September 2016 - 06:58 AM

As promised, here is some rough-cut footage shot on my A7RII as part of a series I'm doing on the different dive sites in Komodo National Park.

 

The first video is shot entirely using ambient light and underwater auto white balance mode, no picture profile. Depth of the site varies from 3-12 or so meters. Some of the deeper shots (e.g. the turtle, lion fish) are shot using a green water magic filter. The shallower shots such as the coral are shot with no filter. Minimal color correction done in Final Cut Pro X.

 

https://youtu.be/LoQCtNUDCcg

 

The second video is shot using two Gates GT14 lights, mostly in Custom White Balance (5200K). A couple of shots, like that of the anemonie and the sweet lips are in underwater auto white balance mode + the lights. No filters were used. 

 

https://youtu.be/j3UgK5OOaV8



#46 Ammar

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Posted 05 September 2016 - 07:30 AM

bubfff.. thank you very much for your helpful input. The Cine profile looks promising. Will try that indeed. 

 

dreifish.. thank you for the video. I was only able to see the first one as for the second one I keep getting "Private" message. The 1st video is beautiful. Colors are amazing. Slightly off perhaps in my opinion with the turtle and lionfish clip due to the magic filter for sure. 



#47 GeoPaul7

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Posted 05 September 2016 - 08:20 AM

As promised, here is some rough-cut footage shot on my A7RII as part of a series I'm doing on the different dive sites in Komodo National Park.

 

The first video is shot entirely using ambient light and underwater auto white balance mode, no picture profile. Depth of the site varies from 3-12 or so meters. Some of the deeper shots (e.g. the turtle, lion fish) are shot using a green water magic filter. The shallower shots such as the coral are shot with no filter. Minimal color correction done in Final Cut Pro X.

 

https://youtu.be/LoQCtNUDCcg

 

The second video is shot using two Gates GT14 lights, mostly in Custom White Balance (5200K). A couple of shots, like that of the anemonie and the sweet lips are in underwater auto white balance mode + the lights. No filters were used. 

 

https://youtu.be/j3UgK5OOaV8

Thanks Dreifish.  I agree the first video is amazing!  That is underwater white balance and no filter?  That sure opens up possibilities, as one could use lights on the same dive, without surfacing to take off the filter.  

 

Question:  How deep do you think you can go with the Underwater white balance able to do the job -- without a filter?  How shallow can you be and still use the underwater auto white balance, rather than auto white balance?  AGain, your video here is something to aspire to, and I love the drone shot too!

 

I can't see the second video either.  Would love to see it!

 

Thanks for posting!



#48 Ammar

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Posted 05 September 2016 - 09:15 AM

By the way gents... did anyone of you used a fisheye lens on the A7S or A7R cam?



#49 GeoPaul7

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Posted 05 September 2016 - 09:34 AM

By the way gents... did anyone of you used a fisheye lens on the A7S or A7R cam?

I used the Nauticam "Wet wide angle lens."  and a 28 mm inside the housing.  They don't describe it with an equivalent mm, but rather they say it gives a 120 degree view.  I haven't tried to determine what mm equivalent that is.

 

I personally would be interested in comparing the quality of the Nauticam Wet wide angle with something that was exclusively Sony on the inside of the housing.  I just accepted the advice of the Backscatter saleman.


As promised, here is some rough-cut footage shot on my A7RII as part of a series I'm doing on the different dive sites in Komodo National Park.

 

The first video is shot entirely using ambient light and underwater auto white balance mode, no picture profile. Depth of the site varies from 3-12 or so meters. Some of the deeper shots (e.g. the turtle, lion fish) are shot using a green water magic filter. The shallower shots such as the coral are shot with no filter. Minimal color correction done in Final Cut Pro X.

 

https://youtu.be/LoQCtNUDCcg

 

The second video is shot using two Gates GT14 lights, mostly in Custom White Balance (5200K). A couple of shots, like that of the anemonie and the sweet lips are in underwater auto white balance mode + the lights. No filters were used. 

 

https://youtu.be/j3UgK5OOaV8

Hi Andrei:  What lenses were you using, particularly on the first, as I can't see the second yet?  thanks. 



#50 TaxiDiver14

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Posted 05 September 2016 - 11:38 AM

Thanks for all that technicall info. As I said slog is not for UW shooting. Camera right out of the box is good.

Yes you will have issues with WB. But get it easy...

Using lights AWB playing a litle with color matrix.

No lights UAWB playing with color matrix depending on water colour and depth.

In my old NEX6 (do not has PP nor UAWB), that perform well.

What I have seen in sony sensors is that you allways need to add red in post. So I will play with PP adding some red saturation an reducing some green. But this will be latter.

Im finishing editing my last trip to Red Sea with the NEX6 and I will post the raw and corrected clip.

Thanks you all for helping, this in being very interesting post.

Edited by TaxiDiver14, 05 September 2016 - 11:52 AM.


#51 dreifish

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Posted 05 September 2016 - 04:54 PM

Thanks Dreifish.  I agree the first video is amazing!  That is underwater white balance and no filter?  That sure opens up possibilities, as one could use lights on the same dive, without surfacing to take off the filter.  
 
Question:  How deep do you think you can go with the Underwater white balance able to do the job -- without a filter?  How shallow can you be and still use the underwater auto white balance, rather than auto white balance?  AGain, your video here is something to aspire to, and I love the drone shot too!
 
I can't see the second video either.  Would love to see it!
 
Thanks for posting!


I changed the settings on the second video. Should be viewable now.

UAWB works great from 0-10 metres usually. It actually works ok on land too (try it for yourself -- I've forgotten it in this mode a few times when filming on the boat) so I don't think you need to worry about getting too shallow.

Keep in mind though that the shots at the beginning of the Mawan video are basically the most ideal conditions you could hope for for underwater ambient light filming -- 3-5 meters depth, midday, bright sun behind me, 20m+ visibility. Basically any camera should do well in such conditions, so I think the quality of the video says more about the conditions than sony's white balance capabilities underwater.

Now that I have video lights, I don't use a filter anymore. I basically shot with ambient light in AUWB mode down to 7-8 meters, and custom white balance 5200k and lights below 15. 8-15m is an interesting area where I'm still experimenting. I hope to get AUWB + lights to work together in this area, because lights alone create a harsh transition between the lit foreground and unlit background. But I may need cooling gels for my lights.

#52 Ammar

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Posted 06 September 2016 - 01:55 AM

I used the Nauticam "Wet wide angle lens."  and a 28 mm inside the housing.  They don't describe it with an equivalent mm, but rather they say it gives a 120 degree view.  I haven't tried to determine what mm equivalent that is.

 

I personally would be interested in comparing the quality of the Nauticam Wet wide angle with something that was exclusively Sony on the inside of the housing.  I just accepted the advice of the Backscatter saleman.

 

It seems so far there isn't a good fisheye lens option to the cam UW. The Sony 16mm f/2.8 Alpha Fisheye lens requires Sony A to E mount adapter that will not fit into the housing due to its large diameter, and Canon 8-15mm fisheye lens requires a Metabones adapter that according to Metabones itself is unreliable when it comes to continuous focus while shooting movies and closeup shots.

 

dreifish, love the second video as well. Good job.

 

My theory is since lights (strobes or videos) restore colors underwater, is not to use any filter or change the color matrix of the WB to avoid any unwanted extra color cast especially red. Without lights however, filters and/or WB customization will be required. This is according to my modest UW still photography experience.

Expose first for the background without the lights to get the desired blue and use the lights to fill the subject.



#53 dreifish

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Posted 06 September 2016 - 03:33 AM

By the way gents... did anyone of you used a fisheye lens on the A7S or A7R cam?

 

So, my Mawan video is shot entirely with a mild fisheye lens -- actually, two. Parts of it are using the Sony 28mm + Nauticam WWL-1, both in full frame mode (120-130* FOV) and APS-C crop mode. I also used my Canon 8-15mm + (sometimes Kenko 1.4x TC) in both full frame and APS-C crop. The filtered shots are all with the 28mm/wet lens combo. I haven't filtered the Canon 8-15mm, which I use with a cheap ($100) Photodiox adapter. 

 

A few thoughts -- I love fisheye for photos, both at 15mm and at 8mm for circular fisheye effects -- my favorite way to shoot reef scenes.  You can see, for example, my profile pic, and other examples on my website.  However, for video, fisheye distortion can be quite distracting in shots where the camera is moving. So I tend to try to mitigate the fisheye look as much as possible -- by shooting in APS-C crop mode and with the TC in the case of the Canon. So the end result is only moderately fisheye, but still a bit wider than the 16-35mm at 16mm.

 

Having used both the Canon 8-15mm and the 28mm + Nauticam WWL-1, I ended up selling the second combination. Why? Because for photos, 130* is not wide enough for me -- I always found myself wanting to go wider. And for video, I don't really use a fisheye very often at all, and when I do, I shoot it at 15mm + 1.4xTC + APS-C mode. So effectively, a 31.5mm fisheye. Which I think pretty much corresponds to the widest end of the 16-35mm rectilinear lens. 

 

In terms of image quality, I saw no difference between the 8-15, with or without TC, and the 28mm/WWL-1 combo. If anything, the 8-15 is sharper, which I found strange, since everyone else seems to think the 28mm/WWL-1 combo is the bomb. For me, the 8-15 has several advantages over the WWL-1:

  • a wider range. Combined with the 1.4x TC and APS-C crop mode on the A7RII, I can go from 8mm circular fisheye all the way to 31.5mm fisheye. The Tokina 10-17 that everyone loves on APS-C cameras can only do 15mm-25.5mm by comparison, or up to 36.5mm fisheye with a 1.4x TC. But it lacks the circular fisheye at the wide end, and that's very important for me for images.
  • no need to deal with the super-heavy front element (WWL-1) skewing the housing trim
  • can be used with a 140mm dome (roughly same size as the WWL-1, same CFWA ability) or with a larger 200 or 230mm dome for split shots (split shots are very difficult with the WWL-1 because the water between the back of the WWL-1 and your port)

 

 

 


Hi Andrei:  What lenses were you using, particularly on the first, as I can't see the second yet?  thanks. 

 

As for the first video, see above. The second video, Batu Bolong, is shot entirely on the 16-35mm behind the Nauticam 8.5" dome. This is the combination I currently favor for video shooting because of it's amazing versitility on the A7RII. Since I can shoot 4k at either full frame or with an APS-C crop, the Sony 16-35mm lens gives me an effective focal length from 16mm - 50mm. Outside of macro situations, I'd say there's very little underwater you can't shoot well with that range. And I've even gotten some nice footage of a flamboyant cuttlefish (roughly palm-sized) with it.

 

This is a bit of a tangent, but as the Backscatter guys mentioned in their review, I feel the A7RII has some very distinct advantages when filming 4k underwater because of the ability to film either in full frame mode or APS-C crop. This means I can get both wide, medium and close-up shots with the 16-35mm, and can get both macro (1.0x magnification) and super-macro (1.5x) magnification with the Sony 90mm lens. Add a flip adapter an a Nauticam SMC-1, and suddenly you can get wide, medium and close-up shots at the macro range, too. No other stills/video hybrid out there offers you that kind of flexibility currently.



#54 dreifish

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Posted 06 September 2016 - 03:48 AM

 

It seems so far there isn't a good fisheye lens option to the cam UW. The Sony 16mm f/2.8 Alpha Fisheye lens requires Sony A to E mount adapter that will not fit into the housing due to its large diameter, and Canon 8-15mm fisheye lens requires a Metabones adapter that according to Metabones itself is unreliable when it comes to continuous focus while shooting movies and closeup shots.

 

dreifish, love the second video as well. Good job.

 

Thanks Ammar!

 

 I absolutely love the Canon 8-15mm on my A7RII. Even with a cheap photodiox adapter, it focuses flawlessly for wide angle pictures. I don't really use it for video, but in general I'd stay away from autofocus in video with any lenses, including the Sony 16-35mm. The way it hunts for focus when you're stepped down to F8 or narrower is very distracting and makes the footage unusable, IMO. I'm not sure if this is because it uses contrast detection instead of phase detection when stepped down past F5.6, but, whatever the reason, it basically means autofocus is unusable underwater in video. I always prefocus (back-button focus) before I start filming. If I have to refocus during the shot, I pretty much treat it as a new shot from then on. 

 

The only problem I have with the Canon 8-15 is that, with Nauticam, it requires a step-up n100 to n120 port adapter + 1 (or 2) extention rings. This is a bit clunky, at it also means you have to mount the lens from the front, you can't insert the camera into the housing with the lens already mounted. That would be a minor annoyance, but it quickly becomes a major annoyance when you realize that the A7RII burns through batteries incredibly fast. If I'm shooting video, I have to switch batteries after every dive. For photos only, you may be able to make a battery last 2 dives, but I would not feel comfortable trying for 3 unless I barely used the camera on the first two dives. Since I do a lot of day trips where the boat goes out for 3 dives, that means I have to open up the housing twice on the boat, take the dome off, take the lens off, open the back, take the body out, replace the battery, put the body back in, put the lens back on, and replace the dome. This is a nightmare situation during a 1 hour surface interval.  This, along with the limited underwater white balance options, is why I'm contemplating a different camera for my current work.

 

 

 

 

My theory is since lights (strobes or videos) restore colors underwater, is not to use any filter or change the color matrix of the WB to avoid any unwanted extra color cast especially red. Without lights however, filters and/or WB customization will be required. This is according to my modest UW still photography experience.

Expose first for the background without the lights to get the desired blue and use the lights to fill the subject.

 

This approach works well for wide-angle photo shooting. It also works for wide angle video, but with the caveat that video lights are much weaker than strobes. Even with two 14000 lumen lights, I can only really fill the foreground to maybe 50cm in front of the lights. So it works, but only for smaller subjects. You're never going to be able to fill in a 2m gorgonian sea fan, as you might if shooting a CFWA still. 



#55 dreifish

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Posted 06 September 2016 - 03:53 AM

If I may just add one more argument to that great summary from dreifish for not shooting SLOG underwater:  Due to its curve SLOG is not really ideal for low light situations and you are much more likely to get blocking and noise.  

 

This is due to the fact that in SLOG you got lots of dynamic range at the highlights, but this comes at the expense of not so much dynamic range in the lowlights / midrange. However, as protecting highlights is not the key issue for underwater filming I would use "normal" or Cinegamma Settings (PP5 or 6 on the A7SII if I recall correctly) instead.

 

 

Bubffm, have you tried shooting with the Cinegamma Settings? In theory, a cinegamma setting that preserves the rec709 color space may be a good compromise with a slightly wider dynamic range/better highlight rolloff than no picture profile, while avoiding the messed up colors of SLOG/SGAMUT. That seems to more or less play out on land.

 

I've yet to do a thorough comparison myself underwater - it would be great if someone could!



#56 bubffm

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Posted 06 September 2016 - 04:02 AM

 

Bubffm, have you tried shooting with the Cinegamma Settings? In theory, a cinegamma setting that preserves the rec709 color space may be a good compromise with a slightly wider dynamic range/better highlight rolloff than no picture profile, while avoiding the messed up colors of SLOG/SGAMUT. That seems to more or less play out on land.

 

I've yet to do a thorough comparison myself underwater - it would be great if someone could!

 

 

No, unfortunately not as I am using the AX100 underwater these days.  I just thought I throw this in as a potential hint for you guys. As you say, theoretically it could be a good compromise. Might be worth trying out the next time you get wet :-)



#57 GeoPaul7

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Posted 06 September 2016 - 05:16 PM

 

Bubffm, have you tried shooting with the Cinegamma Settings? In theory, a cinegamma setting that preserves the rec709 color space may be a good compromise with a slightly wider dynamic range/better highlight rolloff than no picture profile, while avoiding the messed up colors of SLOG/SGAMUT. That seems to more or less play out on land.

 

I've yet to do a thorough comparison myself underwater - it would be great if someone could!

Guys:

 

I am leaving for a one-week trip to Grand Cayman next Thursday, and am up for conducting some tests.  Will be diving 2 tanks a day for 6 days, so I will have some time to review footage in the eventing.  

 

Dreifish, what would the advantage be of a Cinegamma setting?  You had be convinced to leave picture profiles alone for the future.  It certainly makes life easier.



#58 TaxiDiver14

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Posted 07 September 2016 - 12:01 AM

I will be leaving on sunday to Palos.
This one is from NEX6 (SONY SENSOR).



#59 Ammar

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Posted 07 September 2016 - 12:59 AM

TaxiDiver... Beautiful video. Love its mood :)



#60 Ammar

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Posted 07 September 2016 - 01:02 AM

Guys:

 

I am leaving for a one-week trip to Grand Cayman next Thursday, and am up for conducting some tests.  Will be diving 2 tanks a day for 6 days, so I will have some time to review footage in the eventing.

 

Wish you good hunting :)







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