White Balance and a Slate - Canon S80

[ocrmaster]

Can someone with a Canon S80 explain to me how do you use a White Balance Slate.

Is that better than using the U/W option?

I understand at different depth one most keep adjusting the White Balance using a Slate.

What settings do I push to be able to use the White Balance Slate?

 

[Jamdiver]

Hello Ocr,

I don't have a Canon S80, A610 actually.
But I can explain to you the reason and advantages of setting white balance instead of using a underwater white balance preset.

As i'm sure you're well aware, with increasing depth underwater, sunlight is absorbed, and the amount of visible light ... the colour spectrum is rapidly altered with increasing depth.
Because absorption is greater for long wavelengths (red end of the visible spectrum) than for short wavelengths (blue end of the visible spectrum), the colour spectrum is rapidly altered with increasing depth.

So how is this relevant to setting white balance manually?

If we can tell the camera which object in the room is white and supposed to come out white in the picture, the camera can calculate the difference between the current colour temperature of that object and the correct colour temperature of a white object. And then shift all colours by that difference.

In essence the camera is compensating for the properties of water as it relates to light absorption.
Why is manual w/b superior to the u/w white balance preset?
Simply because the u/w white balance preset is just that a preset, it cannot compensate or change for all the varying conditions that are present during a dive.

Changing depth, quality of light, or even the particular color of the water.
By setting manual white balance frequently, when changing depths or when the quality of light changes ( it was sunny, but now it's cloudy..) we have the advantage of having the right white balance for those specific conditions.

Bottom line, setting white balance manually is much much better than using the u/w preset, colors are more vibrant and look more natural.
Less post processing would generally be required.

Can't answer your last question as to what buttons would need to be used.
Why not just put the camera in the housing and experiment until you find it.

All you need to set white balance is a white object, doesn't have to be a dive slate.
Can be pieces of a styrofoam container, white plastic, whatever.

 

[jonix]

the sandy bottom can also substitute for a slate...although at times with slight underexposure

 

[clgsamson]

read...read..read...blah..blah...Jam, you just gave me a headache!

 

[ocrmaster]

Hello Ocr,

I don't have a Canon S80, A610 actually.
But I can explain to you the reason and advantages of setting white balance instead of using a underwater white balance preset.

As i'm sure you're well aware, with increasing depth underwater, sunlight is absorbed, and the amount of visible light ... the colour spectrum is rapidly altered with increasing depth.
Because absorption is greater for long wavelengths (red end of the visible spectrum) than for short wavelengths (blue end of the visible spectrum), the colour spectrum is rapidly altered with increasing depth.

So how is this relevant to setting white balance manually?

If we can tell the camera which object in the room is white and supposed to come out white in the picture, the camera can calculate the difference between the current colour temperature of that object and the correct colour temperature of a white object. And then shift all colours by that difference.

In essence the camera is compensating for the properties of water as it relates to light absorption.
Why is manual w/b superior to the u/w white balance preset?
Simply because the u/w white balance preset is just that a preset, it cannot compensate or change for all the varying conditions that are present during a dive.

Changing depth, quality of light, or even the particular color of the water.
By setting manual white balance frequently, when changing depths or when the quality of light changes ( it was sunny, but now it's cloudy..) we have the advantage of having the right white balance for those specific conditions.

Bottom line, setting white balance manually is much much better than using the u/w preset, colors are more vibrant and look more natural.
Less post processing would generally be required.

Can't answer your last question as to what buttons would need to be used.
Why not just put the camera in the housing and experiment until you find it.

All you need to set white balance is a white object, doesn't have to be a dive slate.
Can be pieces of a styrofoam container, white plastic, whatever.

Thank you sir!

 

[Peter Guy]

On a recent trip I played with using the UW setting, Auto WB and Manual WB on my S80. I confess I didn't see much difference in the "natural" picture and none after post-processing.

BTW, my general post-processing technique has been to identify what I believe to be the blackest point and then, using the eye dropper in levels, set black. It seems to work (although being color blind what do I know).

I'm still waiting for someone to hack the S80 and activate RAW!







(BTW, kidding about being color blind.)

 

[Jamdiver]

Thank you sir!

No prob, i'd also mention that if you're going to use the flash for shots.
You must set manual white balance with the flash on, if you're going to be taking shots without the flash, set manual white balance with the flash off.

Also i've found that for macro shots, i.e. those in which you are very close to the subject less than a foot for example.
Taking shots (using the flash) with the white balance set manually or underwater white balance preset doesn't yield much difference as there isn't much water to filter out the light before it hits the subject.

There are limits to setting white balance manually though, i've found that it works best in relatively shallow (say less than 50ft) with good visibility.

Best of luck to you and as you alluded to in a previous post, one can only do so much before it becomes painfully obvious that a strobe is needed :14:.

 

[ocrmaster]

Jam

how i am thorn over getting a 30d or the Rebel XT.

 

[Jamdiver]

Jam

how i am thorn over getting a 30d or the Rebel XT.

See here...
http://www.scubaboard.com/showthread.php?t=120748

I think this would best answer your question if it pertains to using the dslr underwater.
Analyze your needs, your goals, where you are currently in terms of proficiency with the camera, where you want to be in the future et cetera...

It's the photographer not the camera as they say and having a more expensive camera won't necessarily yield better photos.

As to whether the 30D or Rebel XT... I honestly couldn't tell you, think both are exceptional cameras..
Check out dpreview for a side by side comparison of them for starters..
Regards......

 

[clgsamson]

Jam

how i am thorn over getting a 30d or the Rebel XT.

I thought you wanted a Canon 5D...