white balance ?'s

[jon m]

hey all-
my buddy has a sea-n-sea 750 (dc?)
anyway, it has an option where you set the balance to "custom"
i assume this will help remove blue color? and that to do this you set it to custom, and take a picture (per instructions) of a white object underwater? then the camera can recognize what "white " is and filter out other unwanted(blue)colors?
am i correct so far? (if not let me know)....
my questions are-how is this done?
i was thinking of using the slate underwater? but if that IS how you do it, how far away should the slate be?
how do you do it?
thanks from a photo newb!!

 

[AndyT]

I seldom use custom WB but if I can I just use the sand as a reference. If using a slate I usually make sure it fills around 75 % of the frame - make sure it isn't in shadow .

 

[diver 85]

I just started shooting digital after 12 years of 35 mm & WB is what really threw me @ 1st.....I had no luck with a white slate UW & found out thru trial & error while on Little Cayman just shooting a patch of light colored anything, sand, reef etc worked great....see my pics from LC & the Flower Gardens in my sig........good luck.....

 

[scubapatton]

I use the folding armband slate (2nd one down)

http://www.scuba.com/scuba-gear-249/Miscellaneous-Slates.html


What I do is go to Custom, then point it straight down on the slate (as noted filling at least 75% of screen or so) and then Setting it - see if the camera has a square box with a dot on it on one of the buttons. Then you can take the photo. Your description of what happens is accurate... It tones down the blues and highlights the reds to compensate for the loss of color at depth.

You need to set the WB though every time you change depth (every 3-5 feet or so) if you want accurate colorization. I took a shot of an orange garibaldi once they came out flaming red because I forgot to change the WB when I ascended a little. If you are changing WB to take macro type shots, then put the slate about the same distance from your camera as your desired distance from teh macro (eg is 6-10 inches from coral/fan/etc, then have slate around 6-10 inches from camera when setting WB. This is why I like the arm slate... I can flip to a "page" to write on, then just keep the top one clean for setting WB.

Hope this helps. Since I have an older camera, I do not have RAW on my camera. RAW wipes out the need for WB control. You can tweak photos pretty good with Photoshop, etc w/o needing to change WB, but I figure, the better I get at it underwater, the better my shots come out unchanged...

 

[Gilligan]

I use custom white balance on every non-strobe shot otherwise you have blue photos. I carry a small cut out section of white laundry detergent jug and have it clipped to the tether my camera is on. A dive slate works fine. If you have access to light color sand that works also.

Changing the calibration depends on the amount of ambient light loss/gain at varying depths. I still post process the photos in Photoshop.

When calibrating the custom white balance be sure the white card fills the entire lens and there are no shadows.

 

[jon m]

thanks!

 

[Xarifa]

My dive slate is not really white-white ---it's kind of an off-white, light-tan.
I imagine a white-white slate would provide a better w/b?

Anyone found any differences?

Gilligan - I'm thinking the chunk of laundry jug you use is white-white, and easy to work with as well. How small is it? Did you cut this out of the side or use the bottom? (I'm thinking of a bleach jug, I guess).

 

[kapula]

I always use custom/manual white balance when I don't use a strobe. For white balancing I have a slate or actually it's a piece of a broken sunchair with some rubber band to attach it to my bcd. Fits nicely inside any bcd pocket. When doing the white balancing try not to shade your slate with your camera/housing and do it every time light conditions change. That is if you ascent, descent or sun is blocked etc. It's better to do too often than too seldom. If you white balance deep and go shallower you get very red pictures. On the other hand below 20metres manual w/b looses most of it's use since not that much red light can get that deep anyway.
Hope this helped a bit.

 

[jonix]

I always use custom/manual white balance when I don't use a strobe. For white balancing I have a slate or actually it's a piece of a broken sunchair with some rubber band to attach it to my bcd. Fits nicely inside any bcd pocket. When doing the white balancing try not to shade your slate with your camera/housing and do it every time light conditions change. That is if you ascent, descent or sun is blocked etc. It's better to do too often than too seldom. If you white balance deep and go shallower you get very red pictures. On the other hand below 20metres manual w/b looses most of it's use since not that much red light can get that deep anyway.
Hope this helped a bit.

i do the same with kapula. just to make sure, i calibrate white balance just before taking a shot at depth.

 

[Gilligan]

My dive slate is not really white-white ---it's kind of an off-white, light-tan.
I imagine a white-white slate would provide a better w/b?

Anyone found any differences?

Gilligan - I'm thinking the chunk of laundry jug you use is white-white, and easy to work with as well. How small is it? Did you cut this out of the side or use the bottom? (I'm thinking of a bleach jug, I guess).

It's 2.5" X 4.5" and is from an "All" laundry detergent jug which is white. I cut a section from the side panel. A bleach jug should work but I think the plastic is thinner on the sides. The bottom is likely thicker. Necessity is the mother of invention.