Underwater light absorption

[Bill Totolo]

Checked with the ASC manual, all I saw was info on color absorption but nothing on light loss.

 

Are there any formulas or rules of thumb to determine how much more light it will take to light a subject underwater?

[Guest]

Of course that depends on how deep you go, water clarity, type of day (overcast or not).

 

The ASC manual probably told you about the drop off in the red spectrum at about 15ft. This can be largely corrected via the use of a red filter.

 

I have shot lots of underwater film and video in the Caribbean. The water visability was excellent up to 100 ft and it was always a bright sun with clear skies. At 65 ft you'd be surprised how bright it is. Under those conditions I often will not use any electrical light because on wider shots it creates a "glow" in the centre of frame that looks un-natural. I'm sure you've all seen this look in shows about ocean life. Up close the lights work better if they don't have to cover as wide a space.

 

So I'd have to say it depends on what type of look you want and the other characteristics I mentioned above.

 

R.

 

PS: If you're shooting 35mm underwater then the Kodak 250D works very well.

[Delorme Jean-Marie]

yes u only want to use unde water special light meter.

watchout if you have to focus, marks are different from air marks.

[Bill Totolo]

Thanks for the tips guys. Nothing beats real world experience.