Re: You use different lenses underwater because the speed of light is different

Celcius wrote:
> Hi Dave!
>
> Please explain why on my Nikonos camera, I had a 35mm lens which could
> photograph both underwater and and land? Just curious.

The basic answer is simple: its outermost lens element is FLAT.

With a flat port, the density of the outer medium (here its air or
water) and thus any variations in refration geometry simply doesn't
enter into the question, so the lens is able to focus just fine in both
mediums.


> The only other factors that I know of is that underwater, things seem
> closer than on land...

Which happens to be a side effect of that flat port


> ... and warm colours disappear as you go deeper.

Whixch happens to be a variation in spectral absorbtion because water
isn't a good neutral density filter.


And finally, the only possible reason why <rec.arts.marching.drumcorps>
was listed must have been because it always rains buckets during the
"The Battle of the Bands" competition, according to Funky Winkerbean's
Band Director Harry L. Dinkle: it doesn't take an Einstein to realize
that a waterproof camera is approprate to document this competition
Headers adjusted.


-hh