Does anyone have any opinions about using a red filter with my 15mm?
Alex Mustard had an excellent article in UWPhoto magazine about this. The Sigma 15mm FE has a rear filter holder that takes gel filters.
I had to learn this so I'll explain in case you don't know. I still have to try this myself but it is definately on my list to experiment with this November in Cozumel.
The gel filters are small flexible clear plastic swatches that you trim to fit the holder. They are cheap <10 and you get them in different strengths like CC10R, CC40R etc. for Color Correcting the strength value and Red (or M for Magenta). Ryan recommends the Magenta, Alex suggests the Red. You can stack the filters to create the strength you want.
Ryan Suggests:
30 was a good starting strenth for me, but I expect to use 10-20 in shallow water, and 50+ for some deeper stuff to compare the effect.
Generally speaking, red filters are used without strobe lighting
Karl is basically right here but just because you have strobes is no reason not to experiment with this. I've seen some great results in relatively shallow water with filters. The advantage you have is in bringing color to a large area, like a shipwreck or reef scenic that you could never light with a strobe. Additionally, if you use the magenta filters as Ryan suggests you can use green filters on your strobes and get great balanced light in the foreground with good color in the background.
Also: re color balance controls. If you can shoot RAW, then just shoot RAW and adjust the color balance at home. I think this is easiest and affords the most flexibility. Even in jpg mode you can do wonders with autolevels and a bit of fine tuning in photoshop.
So much to try. Have fun!
