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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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#301 dreifish

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Posted 12 June 2017 - 04:19 AM

FCPX, Davinci Resolve and Premiere don't display that kind of data as far as I know.

 

For those coming late to this thread, let me attempt a short summary:

 

For great colors using the Sony cameras (A7, A7II, A6300/6500 line), you really need to shoot with powerful video lights (WB manually set based on the color of your lights). To allow the lights to compete with the ambient light, you're best off shooting early in the morning or in the last hours before sunset when there is less overall ambient light or at depth (30+ meters) where again there is less ambient light to outcompete. Under these circumstances, it helps to underexpose the background around -0.7 to -1.3 EV to get nice richly saturated blues while adjusting the strength of your lights to avoid overexposing the subjects (use the zebras to check for overexposure.)

 

There's no need to shoot in SLOG or any of the cinegammas if you apply the above exposure principles, as the dynamic range of your scene will fit well within the 7-8 stops of exposure you get under standard picture modes or REC709. 

 

Forget about trying to shoot without lights and doing a manual white balance. Your results will be disappointing unless you're in very clear water and very shallow (5-10m max). In those circumstances, the Underwater Auto White Balance mode can work ok.

 

My experiments using red filters and manual white balance have been pretty frustrating and disappointing overall, so it's not an option I would recommend.



#302 TaxiDiver14

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Posted 12 June 2017 - 04:28 AM

Frames of the day...

Jackson, Gordon and Woodhouse Reefs...

2343407dab0cbc7ccdd29d531505c393.jpg0ef0486a8e1225285a0ef7da3e9fca72.jpgc604039e899569169b3ab18b7d347115.jpg

Edited by TaxiDiver14, 12 June 2017 - 04:43 AM.


#303 GeoPaul7

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Posted 12 June 2017 - 09:12 AM

Very nice:  Are these frames from the 4K video, or are these RAW files from photographs?

 

 

 

Frames of the day...

Jackson, Gordon and Woodhouse Reefs...

2343407dab0cbc7ccdd29d531505c393.jpg0ef0486a8e1225285a0ef7da3e9fca72.jpgc604039e899569169b3ab18b7d347115.jpg



#304 GeoPaul7

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Posted 12 June 2017 - 09:15 AM

Great summary!  I think this will help those who are new to this page.  Query:  Do you just set the WB to 5.2K, or whatever the temp of your lights are?  What does this do to the color of the water, at a distance, where the light is not illuminating it?  How does this compare to underwater WB using basically the same technique?

 

Thanks for this distillation of wisdom.

 

GLP

 

 

FCPX, Davinci Resolve and Premiere don't display that kind of data as far as I know.

 

For those coming late to this thread, let me attempt a short summary:

 

For great colors using the Sony cameras (A7, A7II, A6300/6500 line), you really need to shoot with powerful video lights (WB manually set based on the color of your lights). To allow the lights to compete with the ambient light, you're best off shooting early in the morning or in the last hours before sunset when there is less overall ambient light or at depth (30+ meters) where again there is less ambient light to outcompete. Under these circumstances, it helps to underexpose the background around -0.7 to -1.3 EV to get nice richly saturated blues while adjusting the strength of your lights to avoid overexposing the subjects (use the zebras to check for overexposure.)

 

There's no need to shoot in SLOG or any of the cinegammas if you apply the above exposure principles, as the dynamic range of your scene will fit well within the 7-8 stops of exposure you get under standard picture modes or REC709. 

 

Forget about trying to shoot without lights and doing a manual white balance. Your results will be disappointing unless you're in very clear water and very shallow (5-10m max). In those circumstances, the Underwater Auto White Balance mode can work ok.

 

My experiments using red filters and manual white balance have been pretty frustrating and disappointing overall, so it's not an option I would recommend.



#305 TaxiDiver14

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Posted 12 June 2017 - 09:24 AM

Very nice:  Are these frames from the 4K video, or are these RAW files from photographs?
 
 
 

This are 4k frames only...

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#306 dreifish

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Posted 22 June 2017 - 12:31 PM

Great summary!  I think this will help those who are new to this page.  Query:  Do you just set the WB to 5.2K, or whatever the temp of your lights are?  What does this do to the color of the water, at a distance, where the light is not illuminating it?  How does this compare to underwater WB using basically the same technique?

 

Thanks for this distillation of wisdom.

 

GLP

 

 

 

Yes, correct. I usually set the white balance to 5200k because that's the temperature of the lights I'm using.  In general, the cooler the white balance (i.e. the lower the kalvin temperature), the more blue the water will look. Alex Mustard wrote a nice article about it some years back now. At 5200k clear tropical water already takes on a nice blue color. A less saturated blue near the surface and a more saturated blue the deeper you go. This is because what you're recording is the color of the sunlight being filtered through all the water between you and the surface. The more water, the more the reds and yellows get filtered out, and thus the more richly saturated the blue. For photography, I usually try to set my white balance even lower (around 4500k) to shift the color of the water column further towards true blue and away from aqua. I then light up the foreground using strobes that have warming gels attached so the foreground subjects render the 'correct' color rather than coming off as too blue.

 

Conversely, setting the white balance to warmer temperatures (say, 10000k) will produce muddier, more aqua/green/grey water backgrounds. It's not a great look in tropical water, IMO. This is essentially what happens when you use the Underwater Auto White Balance mode or try to custom white balance off a white/grey card at depth with or without a red filter. The warmer white balance reintroduces some reds and yellows to your foreground subjects, but turns the water column a desaturated magneta-grey.

 

In temperate waters, a color temperature slightly warmer than daylight like 6000-6500k can make the water column more richly green (emerald) rather than aqua-grey, so that actually can be a stylistic choice.  

 

All of the above is true whether you're shooting with lights or without, as the lights don't illuminate the water, they pass though it. 



#307 TaxiDiver14

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Posted 22 June 2017 - 01:19 PM

Anemone City.... Red Sea.

5000K A3M3. 3x7000 lumens torches.
https://youtu.be/yJKS8J1U-JM


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#308 TaxiDiver14

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Posted 23 June 2017 - 06:56 AM

Batu Bolong... Komodo National Park.

https://youtu.be/Mp04UaBeagY


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