Using "land" lens underwater

[dgn]

Hi,
I'm pretty new to diving and also pretty new to photography but I enjoy it a lot. I have been looking at Wide angle and macro lenses for my WP-DC12 but I think it's too expensive for a beginner. So I just had the idea of using my cheap fotodiox lenses underwater, if I build a holder for them. Has any one tried this and why or why not should it work?

What will the refraction index of water do to the lens if the wideangle lens reduces focal length by 0.5 in air? Will it even be possible to focus?

Are there any air pockets or something that might destroy the lens if used under pressure?

Thanks for any answers
Niclas

 

[haibeis]

Matey....

wide angle:

land lenses are usually made of several elements.....none of which would be waterproofed.
water will get in everywhere - and won't come back out fully either...
if the lenses are multi-coated i am pretty sure salt water will wreck them
i doubt it would focus at all, and would be destroyed on the first dive.

macro - you could try land based diopters - this might work

 

[herman]

Welcome to the board.
Don't waste your time or money on macro either. It will work but without getting onto the physics, the diopter value of the lens is cut to 1/4th the land value when underwater so you need a lot of magnification to get a little effect.
Your best bet is to improve your dive skills and learn to use the camera you have until you can save the pennies to get a better system.

 

[dgn]

Ok thanks for the answers! Looks like it was a crazy idea

 

[haibeis]

Sorry to dash your hopes...

the 570 has some pretty decent macro capabilities on it's own though, so don't feel too bad.
wet lenses and
wide angle is a challenge with anything over 3x zoom - you might be outta luck there,
but hunt around ebay - i found a used 16mm for my first u/w camera within a few weeks....
and no you can't have it ;-)