UW auto white balance lock?

[1fspeed]

Wondering if this might be a work around for my Sony A7c's limited manual WB capabilities...  I've been using a Keldan red filter between my WWL-1 and the 28-60 port getting decent results white balancing off a grey card. It works but I really don't like that piece of glass between the port and wet lens.  it's a pain to mount, easily lost if I remove the WWL underwater and I worry about scratching things.  It's also costs 2 stops of light.

 

I don't exactly understand how UW auto differs from auto white balance, but when I've used UW auto in the past it provides nice color, but it can, and usually does shift mid shot.  So I wondered if I could use UW auto WB, hold my grey card in frame long enough for the camera to adjust then activate WB lock (mapped to a rear button) might be a solution.  No red filter, accurate color, no loss of light... 

 

Lakes still frozen round here so haven't been able to properly try it out.

 

Anyone know anything about underwater auto WB?

Anyone use it with WB lock?

🤙

 

ps. shoot fresh water lakes, generally 2-10 meters, occasionally deeper in Lake Superior.

[Davide DB]

I have a Panasonic and I don't think I have the function you describe. Perhaps those who use Sony can give more accurate advice.

Each brand has its quirks when it comes to underwater WB and I imagine that the lake waters are quite green compared to the sea and this can make a lot of difference on how the camera behaves in doing the white balancing.

 

Why don't you do a simple manual WB on a white card and no red filter?

 

White card, not gray card.

You will find very different opinions about this on the internet but the correct explanation is that the gray card is used (on set) to adjust the exposure while the white card is used to adjust the WB.

Here is the detailed explanation from the most reliable source of all:

 

https://www.xrite.com/service-support/18graycardversesawhitebalancecard

 

My Panasonics within 6 meters in the Mediterranean work fine in AWB giving cool colors that I adjust in post.

If I do a MWB on my wet-notes I get very warm colors, maybe too much, and then in post I intervene again by removing some of the reds.

 

[1fspeed]

Manual WB without the filter gives poor color and inconsistent results. Repeated manual white balances at the same depth, same ambient conditions just minutes apart have very different colors. I've heard it has something to do with the A7c maxing out at 9900K.

 

no question x-rite is correct...  my camera often reads the white card as being too bright to complete a manual WB, and with the red filter in place, the white and grey card  give similar manual white balance readings. I honestly don't care about super accurate color, I just want consistent color.

 

Maybe I'll bring the white card along next time.

 

Thanks for the input.

 

 

[Davide DB]

4 hours ago, 1fspeed said:

my camera often reads the white card as being too bright to complete a manual WB

 

It's normal, just close the iris. You have to correctly expose on the white card. During MWB the camera shots a photo and the white card reflect a lot of light.

On a summer sunny day @6m here I MWB at F16/F22

[Chris Ross]

5 hours ago, 1fspeed said:

Manual WB without the filter gives poor color and inconsistent results. Repeated manual white balances at the same depth, same ambient conditions just minutes apart have very different colors. I've heard it has something to do with the A7c maxing out at 9900K.

 

no question x-rite is correct...  my camera often reads the white card as being too bright to complete a manual WB, and with the red filter in place, the white and grey card  give similar manual white balance readings. I honestly don't care about super accurate color, I just want consistent color.

 

Maybe I'll bring the white card along next time.

 

Thanks for the input.

 

 

It could be due to colour temp limitation or could be due to technique of WB reading, from what I understand the exposure used for WB needs to be a "good" exposure and it should be taken in same light as your subject.  Same light means in this context at about the same distance.  I assume you are shooting ambient light as you didn't mention lights so the effect may not be as big, but if you take a WB image of a slate on your wrist you could be shading the slate with the camera and your body.

 

The fact that you get UW auto to work tends to indicate an issue with the way WB is being done, normally I wouldn't expect the colour temperature range to be significantly greater in auto compared to what can be set manually.  Perhaps a white patch on your fin could be used - it would be closer to subject distance and could be oriented to get a shot in same light as subject.  I'm assuming UW auto is an option available for WB from the camera menu.

[1fspeed]

Might be technique - I've used a white patch on my fin, but generally a card held at arms distance and oriented in the direction of the intended shot.  

 

and you're correct - no video lights.

 

I wondered if there is a red channel boost built in to the UW auto WB setting...

[Chris Ross]

2 hours ago, 1fspeed said:

Might be technique - I've used a white patch on my fin, but generally a card held at arms distance and oriented in the direction of the intended shot.  

 

and you're correct - no video lights.

 

I wondered if there is a red channel boost built in to the UW auto WB setting...

It's possible it does that - you could check by comparing the red channel histogram between the two options.  Be easist to do on land shooting in daylight through something like a Wratten 80A filter.  Shoot identical exposures one manual WB and one UW WB.  It's probably not perfect but might be enough red removal to see if there is a noticable difference in the red channel.

[Davide DB]

I remembered we had a Sony's WB similar discussion time ago on Wetpixel and I recall this video.

IDK if it's the same problem. If I understand correctly, in the comments the guy (maybe he is here 🙂 ) wrote few months ago that Sony never solved the problem and the underwater auto wb is the way to go.

 

 

[Eric Hanauer]

You’ve got to temper your expectations. UW manual white balance will give you the colors you see without artificial light, not the brilliant colors you would get with video lights. Even then it will require color grading in post. 
 

Finally, using sand or your bare hand for manual white balance is as effective as a white card. 

[1fspeed]

Quote

22 hours ago, Chris Ross said:

It's possible it does that - you could check by comparing the red channel histogram between the two options.  Be easist to do on land shooting in daylight through something like a Wratten 80A filter.  Shoot identical exposures one manual WB and one UW WB.  It's probably not perfect but might be enough red removal to see if there is a noticable difference in the red channel.

Intersting idea... might have to give that a try - thanks

 

[1fspeed]

20 hours ago, Davide DB said:

I remembered we had a Sony's WB similar discussion time ago on Wetpixel and I recall this video.

IDK if it's the same problem. If I understand correctly, in the comments the guy (maybe he is here 🙂 ) wrote few months ago that Sony never solved the problem and the underwater auto wb is the way to go.

 

Wow - that's crazy!  My Sony's not making color shifting like that, it's just that consecutive custom WB have very different colors.  Oddly similar he's arrived at a similar solution... Thanks for sharing - particularly as I've considered upgrading to an A7sIII.

[1fspeed]

20 hours ago, Eric Hanauer said:

You’ve got to temper your expectations. UW manual white balance will give you the colors you see without artificial light, not the brilliant colors you would get with video lights. Even then it will require color grading in post. 
 

Finally, using sand or your bare hand for manual white balance is as effective as a white card. 

Good advice - I'm an old photographer but a very new to video.  Would't it be nice if video WB was as easy to manage as that of a photo RAW file.

 

Not much sand round here and don't think my hand would work either😂

[Jim Laurel]

This mixed light problem is always a challenge. I wish I had a better answer for you, but...the unfortunate truth is that a camera will either white balance at depth or it won't, and the A7C is one of the latter. Then you have ones like the GH5, which will kind of do it, but not very well.

A red filter can help, and the Keldan you mention is the best one you'll find anywhere. You mention a 2 stop light loss, so I assume you're using the SF-2. But even with this filter, you may find that while your colors at depth in ambient light can be ok, you might see things like the surface going magenta when you pan up as an animal swims above you.

With the A7C, there are a few ways to approach it.

1. No red filter and set your white balance to the color temperature of your (presumably daylight color) lights. Everything lit with ambient light will be very blue/cyan, and only those things lit by your lights fairly close (like a few feet away) will have correct color.

2. Use the red filter along with a cyan light, such as a Keldan with an "Ambient" filter, like an AF12. Put your lights on, hold your white balance card arm's length away, and execute a manual white balance. You'll get correct color on objects a few feet away from the camera, and things lit by ambient light will appear a but more natural.

Of course, the best way of all to approach this is with a camera that will white balance at depth. I use the A1, A7SIII, and A7IV, all of which will do a good white balance at depth without a red filter. My technique is simply to turn on my cyan lights, hold the grey card at arm's length so that the cyan light is hitting it, and grab a white balance. This ensures that when an animal passes close to the camera, colors will remain true. There is no red color cast. I go for correct colors on things that are from arm's length to around 5-6 feet away, and let everything else fall where it may. But because I'm white balanced to the cyan lights, even the parts of the frame lit by ambient lights appear natural. I use my old (about 10 years old now) Keldan Luna 8s with the cyan modules, and a pair of the 4X with the AF12B filter. However, since I almost never use daylight balanced lights any more (there's little point to it, really...maybe at night?), I am going to switch to a pair of the new 8XR Ambient soon.

 

I'd recommend against using a white card. Cameras will often fail to capture a custom white balance reading because the white card is clipped. I've seen some very experienced videographers who draw black diagonal lines across a white card with a thick sharpie, presumably to avoid this problem. You could also set exposure lower, but that can take too much time when you've just arrived at a new depth (so you need a new white balance), and an animal is approaching. I use this card from Keldan, which is just an xrite encased in resin. Color checker on one side and a grey card on the other. Works perfectly. Put it on a retract, grab white balance that let it snap back. If you have an extra moment when you start rolling, you can flip it over to the color checker side and show it to the camera as a reference. I grab white balance pretty obsessively whenever depth changes, but I also save white balances to the presets when there's no time to set one manually. That way, at least I'm in the ballpark. 1:~15-20ft, 2:~35-40ft, 3:~60ft  This came in very handy recently in Socorro. We often had dolphins right as we entered the water, so I'd go in preset to the first WB setting. That allowed me to start filming right away as we descended.

Never use auto white balance, because the camera will change it while a clip is being filmed, and you will have a devil of a time chasing a moving white balance when you edit.

The folks over at Behind the Mask did a nice demo video about red filters and cyan lights.

On 4/16/2024 at 2:19 PM, 1fspeed said:

Wondering if this might be a work around for my Sony A7c's limited manual WB capabilities...  I've been using a Keldan red filter between my WWL-1 and the 28-60 port getting decent results white balancing off a grey card. It works but I really don't like that piece of glass between the port and wet lens.  it's a pain to mount, easily lost if I remove the WWL underwater and I worry about scratching things.  It's also costs 2 stops of light.

 

I don't exactly understand how UW auto differs from auto white balance, but when I've used UW auto in the past it provides nice color, but it can, and usually does shift mid shot.  So I wondered if I could use UW auto WB, hold my grey card in frame long enough for the camera to adjust then activate WB lock (mapped to a rear button) might be a solution.  No red filter, accurate color, no loss of light... 

 

Lakes still frozen round here so haven't been able to properly try it out.

 

Anyone know anything about underwater auto WB?

Anyone use it with WB lock?

🤙

 

ps. shoot fresh water lakes, generally 2-10 meters, occasionally deeper in Lake Superior.

 

 

Edited April 24 by Jim Laurel

[Jim Laurel]

Sample video with ambient white balance and cyan lights. Straight out of the camera. Sony A7SIII, Keldan Luna 8 lights with cyan modules. Notice that the small fish that are arm's length from the lens appear with correct colors, while water color is natural, and the sharks in the distance look the way you'd see them with your eyes. Then, as they approach the camera, colors remain natural with no pink or red cast from the video lights.
 

 

Edited April 24 by Jim Laurel

[Interceptor121]

On 4/16/2024 at 10:19 PM, 1fspeed said:

Wondering if this might be a work around for my Sony A7c's limited manual WB capabilities...  I've been using a Keldan red filter between my WWL-1 and the 28-60 port getting decent results white balancing off a grey card. It works but I really don't like that piece of glass between the port and wet lens.  it's a pain to mount, easily lost if I remove the WWL underwater and I worry about scratching things.  It's also costs 2 stops of light.

 

I don't exactly understand how UW auto differs from auto white balance, but when I've used UW auto in the past it provides nice color, but it can, and usually does shift mid shot.  So I wondered if I could use UW auto WB, hold my grey card in frame long enough for the camera to adjust then activate WB lock (mapped to a rear button) might be a solution.  No red filter, accurate color, no loss of light... 

 

Lakes still frozen round here so haven't been able to properly try it out.

 

Anyone know anything about underwater auto WB?

Anyone use it with WB lock?

🤙

 

ps. shoot fresh water lakes, generally 2-10 meters, occasionally deeper in Lake Superior.

Do not white balance in log profile. Use a standard picture profile and it will work much better and never fail

underwater AWB clips the blue giving innatural hues in pretty much all conditions it also creates very strange reds

Edited April 25 by Interceptor121

[Jim Laurel]

Hey Interceptor!. Nice to see you here.

 

--Jim

 

On 4/25/2024 at 12:53 AM, Interceptor121 said:

Do not white balance in log profile. Use a standard picture profile and it will work much better and never fail

underwater AWB clips the blue giving innatural hues in pretty much all conditions it also creates very strange reds

 

[1fspeed]

On 4/24/2024 at 4:11 PM, Jim Laurel said:

Sample video with ambient white balance and cyan lights. Straight out of the camera. Sony A7SIII, Keldan Luna 8 lights with cyan modules. Notice that the small fish that are arm's length from the lens appear with correct colors, while water color is natural, and the sharks in the distance look the way you'd see them with your eyes. Then, as they approach the camera, colors remain natural with no pink or red cast from the video lights.
 

Thanks for mini master class in UW lighting Jim.  Super helpful.  One question.  When you do a white balance you do so with the cyan filtered video lights on?  The Kelvin video suggests doing so when they're off.... but I imagine balancing with the lights on results in a more accurate WB on the lit foreground, at the expense of a somewhat inaccurate WB for the unlit background.

 

Your video is the perfect UW example of what I try to do topside with lighting... make it look like it's not lit.  Beautiful footage!

[1fspeed]

On 4/25/2024 at 2:53 AM, Interceptor121 said:

Do not white balance in log profile. Use a standard picture profile and it will work much better and never fail

underwater AWB clips the blue giving innatural hues in pretty much all conditions it also creates very strange reds

Thanks - I'm new enough to video I've been staying with the Std profile.  From what I understand the A7c's 8bit color limits its color grading potential anyway.

[Davide DB]

Usually I don't like uw Sony colors at all but these are the best colors I saw. I thought they were Canon clips 😉

 

[Interceptor121]

2 hours ago, Davide DB said:

Usually I don't like uw Sony colors at all but these are the best colors I saw. I thought they were Canon clips 😉

 

Sony colors in the A1 are pretty good and the camera white balance works well

[Interceptor121]

3 hours ago, 1fspeed said:

Thanks - I'm new enough to video I've been staying with the Std profile.  From what I understand the A7c's 8bit color limits its color grading potential anyway.

You can try the cine1 or cine2 picture profiles or the rec709 with pro color they are pretty good

[Jim Laurel]

I think I've seen this issue maybe once or twice back when I first started using the A7SIII. I can't remember seeing it at all in the last year at least. Maybe Sony fixed it in one of the firmware updates.

 

On 4/17/2024 at 8:28 AM, Davide DB said:

I remembered we had a Sony's WB similar discussion time ago on Wetpixel and I recall this video.

IDK if it's the same problem. If I understand correctly, in the comments the guy (maybe he is here 🙂 ) wrote few months ago that Sony never solved the problem and the underwater auto wb is the way to go.

 

 

 

[Jim Laurel]

Thanks 1fspeed! Appreciate the kind words. I'm trying to do exactly what you mention, which is to light a scene, so that it doesn't look lit. You can tell from the shadows being cast by the fish and shark fins, for example, but I try not to make it too obvious. I think the background looks more or less the way it looks to your eye when you're actually down there.

In response to your question, yes, I do the white balance with the filtered lights on. My normal practice is to have the lights on at about 2/3 power. The Keldan grey card is on a retract attached to a d-ring. I just pull it out, take the WB at arm's length. I usually have the lights behind the lens, and aimed straight or toed a little outward to reduce backscatter. So the light hitting the card is always a mix of ambient and the cyan lights. The ambient component is higher at shallower depths, and lower at greater depths where there's less ambient light. At shallower depths, I turn the lights up as bright as possible. When deeper, maybe to 2/3 power. Seems to work very well. I know that Keldan suggests taking the white balance with the cyan lights off, and that works pretty well also. In a recent email, though, Daniel Keller told me that when testing the new 8XR Ambient, he was actually setting the white balance with the lights at full power. The 8XR Ambient is an 18,000 lumen light, so that's a heck of a lot of power. He seemed to imply that he was using them unfiltered, so that light would be the equivalent of a Keldan AF6B. I normally use an AF12B on my 4X lights, or the cyan modules in the Luna 8s, which are also equivalent to color temperature of a daylight light head with the AF12B filter.

I'd also say that it's really critical to capture white balance in a way that is completely repeatable. Alot of people I talk to say that they grab white balance from their buddy's tank, or a patch of sand, etc. It can work, but results will vary based on how close you are to the target, the color if it, etc. I find having a small grey card that I can hand-hold to the same distance every time works well.
 

9 hours ago, 1fspeed said:

Thanks for mini master class in UW lighting Jim.  Super helpful.  One question.  When you do a white balance you do so with the cyan filtered video lights on?  The Kelvin video suggests doing so when they're off.... but I imagine balancing with the lights on results in a more accurate WB on the lit foreground, at the expense of a somewhat inaccurate WB for the unlit background.

 

Your video is the perfect UW example of what I try to do topside with lighting... make it look like it's not lit.  Beautiful footage!

 

[Interceptor121]

18 hours ago, Jim Laurel said:

Thanks 1fspeed! Appreciate the kind words. I'm trying to do exactly what you mention, which is to light a scene, so that it doesn't look lit. You can tell from the shadows being cast by the fish and shark fins, for example, but I try not to make it too obvious. I think the background looks more or less the way it looks to your eye when you're actually down there.

In response to your question, yes, I do the white balance with the filtered lights on. My normal practice is to have the lights on at about 2/3 power. The Keldan grey card is on a retract attached to a d-ring. I just pull it out, take the WB at arm's length. I usually have the lights behind the lens, and aimed straight or toed a little outward to reduce backscatter. So the light hitting the card is always a mix of ambient and the cyan lights. The ambient component is higher at shallower depths, and lower at greater depths where there's less ambient light. At shallower depths, I turn the lights up as bright as possible. When deeper, maybe to 2/3 power. Seems to work very well. I know that Keldan suggests taking the white balance with the cyan lights off, and that works pretty well also. In a recent email, though, Daniel Keller told me that when testing the new 8XR Ambient, he was actually setting the white balance with the lights at full power. The 8XR Ambient is an 18,000 lumen light, so that's a heck of a lot of power. He seemed to imply that he was using them unfiltered, so that light would be the equivalent of a Keldan AF6B. I normally use an AF12B on my 4X lights, or the cyan modules in the Luna 8s, which are also equivalent to color temperature of a daylight light head with the AF12B filter.

I'd also say that it's really critical to capture white balance in a way that is completely repeatable. Alot of people I talk to say that they grab white balance from their buddy's tank, or a patch of sand, etc. It can work, but results will vary based on how close you are to the target, the color if it, etc. I find having a small grey card that I can hand-hold to the same distance every time works well.
 

 

The Keldan grey card that i have is an exposure card not a white balance card.

I discussed with Daniel at the time and he told me white balance is not something he was interested in so he was not making one I do not know if things have changed

I do not find the exposure card/color checker very useful to be frank

On Sony system I also agree you no longer need a keldan spectrum filter the camera white balances just great

[Jim Laurel]

This is the one I use from Keldan. It is a standard x-rite color checker classic encased in resin, and the grey side is intended for white balance. From the x-rite website:

 

ColorChecker Passport is a rugged, pocket-sized case that houses and protects three indispensible targets:

• ColorChecker White Balance Target: A spectrally-neutral white balance gray card target for in-camera white balancing for RAW and JPEG photography.
• ColorChecker Classic: The recognized industry standard 24-patch target for fine tuning critical color and building custom DNG profiles.
• ColorChecker Creative Enhancement Target: A Creative Enhancement target for white balance adjustment and exposure verification.

One thing to note is that the grey card on the "passport" size color checker that Keldan supplies may be too small a target for some cameras. In particular, it would be a challenge with some cameras that measure a little outside the white frame presented by the camera during the custom white balance process, so a larger card might be needed.

I can confirm that, for the Sony A1, A7SIII, and A7IV, the grey side of the Keldan card is of adequate size and results in an accurate white balance every time.

I do think you get slightly better color when the red filter is used. But the 2-stop light loss alone is a bigger penalty than slightly worse colors. And in any case, as you say, the Sonys white balance just fine.

 

5 hours ago, Interceptor121 said:

The Keldan grey card that i have is an exposure card not a white balance card.

I discussed with Daniel at the time and he told me white balance is not something he was interested in so he was not making one I do not know if things have changed

I do not find the exposure card/color checker very useful to be frank

On Sony system I also agree you no longer need a keldan spectrum filter the camera white balances just great