If we do our photography snorkeling mainly at depths of no more than say five metres, then there is so much
ambient (natural) light that we can't ignore it.
Up shallow, there is too much to cut out to rely on a strobe or flash as the
dominant light source (as scuba divers often can).
As light passes through water it filters out/ removes red colours first. Even at our shallow snorkeling
diving depths the red is missing.
Then as we go deeper it takes out the orange and way down, finally the blue goes. This means that even at relatively modest snorkeling depths, everything has a blue tinge.
Even something which is in fact white, will appear to be a very light blue in a photograph shot a
few metres down.
Adjusting white balance is the photo editing process of reducing the overly blue tinge to photographs. Note that
we are removing colour ie blue. We aren't adding the red back.
So, white looks really white rather than light blue and pinks look pink rather than mauve etc. But,
in so doing we have lost colour.
What happen's if we ignore 'white balance'?
All four photos below are straight out of their
respective cameras, with absolutely no photo editing at all. None are great shots.
But, both 'pairs' were shot at the same time of day, so were under similar lighting conditions.
Clearly no flash was required.
They were chosen simply on
the basis of near-identical shooting conditions, and
allows direct comparison of the colours.
Hopefully the above show that it is a false saving to spend loads on a tropical holiday and try to save
a hundred or two on a less-than-good, camera and underwater housing.
The comparative photos show that output from a high end compact requires very little colour balance photo editing
Note that the better camera was set to - 'white balance = underwater'. Do not confuse this with using the
'underwater scene' or 'underwater mode' setting which is very different.
In the photo-editing section, options to deal with white balance are discussed, but why fuss, use a decent camera.