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Manual White Balancing the CX550V in the L&M Housings


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#1 uwxplorer

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Posted 01 June 2011 - 09:16 PM

Here is a copy of an exchange I had with Peter Walker. He must be tired of reading the same question over and over again, so he suggested I shared these bits of wisdom;

Hi Peter,

since you have mentioned it a few times, I am curious to know how you salvaged "grainy-red" footage (supposedly resulting from white balancing with insufficient red in the field of view), if you could at all...
I am using FCE, so I may not have access to all the tools you may have in FCS. But I plan to upgrade to FCPX when it comes out (after a short waiting period where I'll attentively listen to user feedback :-).
Interestingly, this happened while I was trying to MWB off my white fin decorated with a generous dose of red in the form of a couple of dive flags (precisely to follow your advice!). After MWB, I got a beautiful white and red fin image, a tad too red image otherwise (but not dramatically so, as I thought looking at my LCD screen).
I only discovered the red graininess once I downloaded my footage on my MBP. It is not dramatic, as I did not use this approach for too many shots, but in case you worked out a solution, I would definitely appreciate your advice.
Best,
X.

PS: I will try to zoom on a red area of my fin next time I attempt this experiment. So far, I have simply framed my fin and MWB. What do you think?

I always look at the blue water through the viewer after every MWB. If it looks even the slightest bit purplish, do another MWB closer to the test subject or with the lights closer or brighter.

As I mentioned, in other threads, I gave up on using fins for MWB. Too awkward and not reliable enough. Now I use sand, coral, rusty metal, etc. If you have framed your fin, I don't know how much the white part of the fin has effected the reading.

It is a case of practice, practice, practice; until your eye can see how the camera's sensor will react.

If you do get a mild case of the red fuzzies, in FCP, I use the 3-way color corrector, with a delimiter set for only the blue-green areas (water) and I drag the color adjuster away from red towards the blue. I play with these until I get the best balance. Depends a bit on the brightness of the water, but I find that the lighter channel needs more than the middle channel, which needs more than the darker channel. Also dropping the brightness of the lighter channel helps. A bit of playing gets it almost right. They never completely disappear but they become almost unnoticeable.

Of course, a severe case of the fuzzies is not salvageable.

If you are ever diving and are unsure if the MWB is right, press and hold and put it back to AWB then try to reduce the green in the color corrector.

Regards
Peter

PS. I suggest you copy this thread back into the forum. There is nothing private about this conversation, is there?

#2 biminitwist

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Posted 07 June 2011 - 01:48 PM

I'm just back from Bali putting the 550V thru some trial and error practicing for a another trip next year and have noticed similar issues to what others have posted with regards to white balance. I found even using the above method it would occasionally still add more red to a scene than I wanted so it is definately going to be a learning curve. I don't usually do a lot of correction in post but may have to learn.
Another strange thing I noticed was some unusal color rendition, for example a fluorescent yellow crinoid would be yellow and some other colors seemed slightly off the colors seen under the lights.
Since I'm just learning the tricks of this camera any suggestions would be appreciated.
Thanks.
John

#3 peterbkk

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Posted 08 June 2011 - 04:37 AM

Since I'm just learning the tricks of this camera any suggestions would be appreciated.
Thanks.
John


Probably not much more that I can add from what I have said here and in other threads on this forum.

Best advice is to "practice, practice, practice; until your eye can see how the camera's sensor will react." Eventually you'll be getting it right NEARLY every time. Best to under compensate for the lack of red rather than over compensate.

Regards
Peter

#4 susaninvirginia

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Posted 08 June 2011 - 10:55 AM

Peter- I hope you agree that there are no stupid questions- here goes. You have mentioned that you use your hand to give the camera some red when MWB. Would it help if one also had red nail polish on? Since I am a woman I wouldn't get weird looks- not that I would care.

I just bought this rig and am excited about it- all because of your other thread. I did find though that the MWB button was not programmed for my camera when I got it- which shows how important your advice is to get familiar with it on the kitchen table first. It was an easy fix but I would not have wanted to be on a trip when I figured it out.

#5 peterbkk

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Posted 09 June 2011 - 02:16 AM

You have mentioned that you use your hand to give the camera some red when MWB. Would it help if one also had red nail polish on? Since I am a woman I wouldn't get weird looks- not that I would care.


Red nail polish might attract amorous male divers - but probably wont do much for MWB. :)

I would only use the hand for a MWB as a fall-back, if there was no other suitable subject in sight. It is actually quite tricky to get the distance and angle correct and hold it while the camera goes through its MWB routine.

Coral, sand, rust all work better.

But, instead of red nail polish, a pink glove might be better than a white hand.

Regards
Peter

#6 CheungyDiver

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Posted 09 June 2011 - 04:55 AM

Red nail polish might attract amorous male divers - but probably wont do much for MWB. :)

I would only use the hand for a MWB as a fall-back, if there was no other suitable subject in sight. It is actually quite tricky to get the distance and angle correct and hold it while the camera goes through its MWB routine.

Coral, sand, rust all work better.

But, instead of red nail polish, a pink glove might be better than a white hand.

Regards
Peter



LOL... how about red fins :) Or brown fins for that matter.

A white board with stripey red lines seems to work. Just vary the stripes and find the right one that works. Some people use red duct tapes.

Just had a crazy idea - I am thinking that a small flat light box with those adjustable LED (the ones with RGB leds). Just vary the colour of the light until the best WB is obtained.

Cheers

David

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#7 peterbkk

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Posted 09 June 2011 - 07:19 AM

LOL... how about red fins :) Or brown fins for that matter.

A white board with stripey red lines seems to work. Just vary the stripes and find the right one that works. Some people use red duct tapes.

Just had a crazy idea - I am thinking that a small flat light box with those adjustable LED (the ones with RGB leds). Just vary the colour of the light until the best WB is obtained.

Cheers

David


Yeah, brown fins would work - about a sort of baby-shit brown. But who would wear them? And doing a MWB off a fin can look at bit weird especially if you have to keep chasing the fin in the viewfinder - might find yourself upside-down or twisted in knots...

But some light panel that lets you simulate a WB using a bank of low-output color-adjustable LEDS might just work. Let's discuss next time we meet.

Regards
Peter

#8 biminitwist

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Posted 10 June 2011 - 11:05 AM

Yeah, brown fins would work - about a sort of baby-shit brown. But who would wear them? And doing a MWB off a fin can look at bit weird especially if you have to keep chasing the fin in the viewfinder - might find yourself upside-down or twisted in knots...

But some light panel that lets you simulate a WB using a bank of low-output color-adjustable LEDS might just work. Let's discuss next time we meet.

Regards
Peter


While in Tulamben I had good luck manual WB ing off the darker sand most times though occasionally I would accidently hit the WB button instead of the record button while trying to rearrange a shot and everything would go pink which would cause me to start over re white balancing on something darker.
For things like the Liberty wreck I ended up WB ing shallow and leaving it as I went deeper.
I had pretty decent blues also if I knew I would be shooting up (the jacks) then I would just manually turn down the exposure as I panned up to till the surface looked good then record.
Just need to sort out better color reproduction, weird it would seem to do most colors accurately but certain yellows and reds would look different than the actual subject. May try a color slate and play around but pretty sure this is WB related as well.
John

Edited by biminitwist, 10 June 2011 - 01:51 PM.


#9 seok

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Posted 05 July 2011 - 08:31 PM

Hey all,

Had a frustrated first few dives but managed to finally get it close to right after I found some tips on google (can't remember where unfortunately!) adds with some tweak and testing on my own. Here's what I do:
- low lux (off)
- auto backlight (off)
- AE shift (-2)
- WB shift (-3)

I think the main reason for the dancing red pixels is when the camera trying to overexpose itself with the auto backlight on.

Hope that helps!

#10 peterbkk

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Posted 05 July 2011 - 09:10 PM

Hey all,

Had a frustrated first few dives but managed to finally get it close to right after I found some tips on google (can't remember where unfortunately!) adds with some tweak and testing on my own. Here's what I do:
- low lux (off)
- auto backlight (off)
- AE shift (-2)
- WB shift (-3)

I think the main reason for the dancing red pixels is when the camera trying to overexpose itself with the auto backlight on.


Yes, clearly the CX550 has some logic to boost gain in the red channel to try to WB back to white. You have to fool it into thinking that it is seeing enough red, either through making sure that there is plenty of red in the WB target subject or by adding red through video lights.

I also have all the same settings - except for WB shift of -3. Never quite understood the concept of a WB shift or how much the numbers actually affected WB.

Very important to have AE set to -2 or -3, or even -4 in dark conditions, to prevent the CX550 from trying to overexpose and boost the gain too much.

For me, MWB success has come from careful selection of the MWB target subject (something brown or pink - lots of red in the target subject during MWB seting) and deciding how much artificial light to include in the MBW. I control the artificial light level by the full, half and quarter settings on the Sola lights and by how close the lights are to the subject during the MWB process. These days I get it right about 90% of the time.

As long as you are diving at around the same depth for most of the dive, you only need to change the MWB setting when the ratio of natural to artificial light changes (e.g. in a cave or inside a wreck). If artificial light dominates, AWB works. If natural light dominates, MWB is best. I just wish that the CX550 would remember and use the last MWB setting because, quite often, it is close enough to correct for a series of dives in similar conditions but, as soon as you press the MWB button, it resets itself and you've got to find a subject and get it set right again. Wouldn't it get be great if you could just switch back from AWB to MWB, with the CX550 recalling the previous MWB setting. it'd be right more often than not.

The new Canon XF100 does just that - with two separate memory registers.

I'm looking forward to getting the Canon XF100 underwater later this month as it can quickly step through 4 WB settings (auto, daylight, and two MWB settings which can either be recalled or overridden). I'm hoping that I can set the two MWB settings on the first dive of a dive trip (e.g. setting A for depths down to 12-15 meters, setting B for depths from 12-25 meters) and, unless conditions change significantly, just flip between the two remembered settings and auto (for deeper depths or places where the dominant light is from the video lights) during a dive without having to set the MWB too often.

Regards
Peter

#11 MentoS

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Posted 14 July 2011 - 03:12 AM

HELLO

I would like to ask You about the configuration for underwater video for Camera Sony cx550 .
Can anyone help me ??

Regards

Mateusz
Best Regards

Mateusz Nowaczyk

http://www.mentos.net.pl

#12 peterbkk

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Posted 14 July 2011 - 03:14 AM

HELLO

I would like to ask You about the configuration for underwater video for Camera Sony cx550 .
Can anyone help me ??

Regards

Mateusz


Ask away.

#13 MentoS

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Posted 14 July 2011 - 03:30 AM

Ask away.


Thanks for answer

I meen my camera basic set up? I need to do some underwater shooting, what settings in menue I should consider?
After my first expirience everything is too green.
Best Regards

Mateusz Nowaczyk

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#14 peterbkk

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Posted 14 July 2011 - 03:41 AM

Thanks for answer

I meen my camera basic set up? I need to do some underwater shooting, what settings in menue I should consider?
After my first expirience everything is too green.


Sounds like your problem is white balance.

Can I suggest you buy the book called "High Definition Underwater Video" by Steven Fish. You can find out where to get it from http://www.fishtales...VideoBooks.html

It will teach you all you need to know about underwater video, including white balance.

Regards
Peter

#15 MentoS

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Posted 14 July 2011 - 03:45 AM

Sounds like your problem is white balance.

Can I suggest you buy the book called "High Definition Underwater Video" by Steven Fish. You can find out where to get it from http://www.fishtales...VideoBooks.html

It will teach you all you need to know about underwater video, including white balance.

Regards
Peter


thanks.

i will buy this.

But thell me abou this specific camera ( cx550 ) what should I set up in my camera menu ??
Backlight , night shot ... etc
Best Regards

Mateusz Nowaczyk

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#16 uwxplorer

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Posted 14 July 2011 - 07:09 AM

Peter is a treasure trove of wisdom, but I am starting to wonder whether he has to fight the green water conditions that we cold water divers often time encounter!
This being said by a relatively inexperienced videographer, I tend to not think green is necessarily bad, if the true color of the water is actually green. The problem you might be facing is more likely that you have less red that you were hoping for (hence everything is looking green). If that's not the question, my apologies.
Check out this thread and another one started by Peter when he bought the CX550V and progressively discovered its quirks (he now is moving to "greener" pastures, if I may say).
The main issue with that camcorder is that the MWB algorithm does not function well at depth (when there is very little red to be seen in the first place). If you MWB off a white slate or fin at depth, the CX550 will try to artificially boost the red and that's not what you want: you get a noisy red image. Sometimes, it is possible to achieve a decent result by using MWB on a scene that contains already some red. Somehow that tricks the algorithm to slightly enhance the red gain, but not to the point of turning your scene in a blood bath.
There are two practical solution to this problem:
1) MWB at moderate depth (to be precise, when you still have enough ambient light to have some red in your scene, and that will depend on the day and location). Do not reset it inadvertently at depth, or you will have to fight (hopelessly) the problems evoked before.
2) Use lights (bright ones) to inject some red photons in the scene. Obviously that won't be enough for wide-angle shots of a wreck 30 ft away... But for close-up, even AWB will work in these conditions.
Good luck and practice, practice, practice!

#17 MentoS

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Posted 14 July 2011 - 08:28 AM

Peter is a treasure trove of wisdom, but I am starting to wonder whether he has to fight the green water conditions that we cold water divers often time encounter!
This being said by a relatively inexperienced videographer, I tend to not think green is necessarily bad, if the true color of the water is actually green. The problem you might be facing is more likely that you have less red that you were hoping for (hence everything is looking green). If that's not the question, my apologies.
Check out this thread and another one started by Peter when he bought the CX550V and progressively discovered its quirks (he now is moving to "greener" pastures, if I may say).
The main issue with that camcorder is that the MWB algorithm does not function well at depth (when there is very little red to be seen in the first place). If you MWB off a white slate or fin at depth, the CX550 will try to artificially boost the red and that's not what you want: you get a noisy red image. Sometimes, it is possible to achieve a decent result by using MWB on a scene that contains already some red. Somehow that tricks the algorithm to slightly enhance the red gain, but not to the point of turning your scene in a blood bath.
There are two practical solution to this problem:
1) MWB at moderate depth (to be precise, when you still have enough ambient light to have some red in your scene, and that will depend on the day and location). Do not reset it inadvertently at depth, or you will have to fight (hopelessly) the problems evoked before.
2) Use lights (bright ones) to inject some red photons in the scene. Obviously that won't be enough for wide-angle shots of a wreck 30 ft away... But for close-up, even AWB will work in these conditions.
Good luck and practice, practice, practice!

thanks for all

I try this on next weekend .

I ask You because i think that i hove something wrong in my camera menu .
I think about this two functions :

1) Backlight shot
2) Night shot
i don't know exectly what is better to turn off or on.
I have to buy an amphibico HD EVO housing for this camera and 95 deegres lens and the effect is when i shot on land my picture is moving. Like waves. this effect is in water too.
i try to make something in camera menu ...
Thanks for all
Best Regards

Mateusz Nowaczyk

http://www.mentos.net.pl

#18 peterbkk

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Posted 14 July 2011 - 08:49 AM

Peter is a treasure trove of wisdom, but I am starting to wonder whether he has to fight the green water conditions that we cold water divers often time encounter!


After all the help I've given you over the last few months, you are now questioning my credibility? You suggest that I am only capable of shooting video in perfect condiitions? Let me tell you young laddie, I was shooting in murky green cold water when you were still in diapers. And I often encounter less than perfect conditions here where i live now. Take a look at my website. For example, the Singapore Seahorse video was shot in water of about 2 meter visibility; thick green soup. it's not about conditions, or the camera, it's about building up the experience and knowledge to get the best out of any situation...

#19 peterbkk

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Posted 14 July 2011 - 08:54 AM

thanks for all

I try this on next weekend .

I ask You because i think that i hove something wrong in my camera menu .
I think about this two functions :

1) Backlight shot
2) Night shot


Turn them off. Any in-camera image enhancement, other than the optical stabilizer, is not going to help underwater. They are designed to help in normal above-water conditions and will only act unpredictably underwater.

Regards
Peter

#20 peterbkk

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Posted 14 July 2011 - 08:57 AM

I have to buy an amphibico HD EVO housing for this camera and 95 deegres lens and the effect is when i shot on land my picture is moving. Like waves. this effect is in water too.
i try to make something in camera menu ...
Thanks for all


Post a short sample of the "waves" and someone might be able to suggest what is causing the problem.

Regards
Peter