hi everyone, I'm getting ready for few days worth of trip to Okinawa - the least Japanese part of japan. Snorkeling included and therefore I would like to try my skills with underwater photography (in a way that won't suck out my wallet ), that calls a question for light metering (depending on my camera choice). I do know that underwater meters exist but not sure of I can find one, is there any major difference from normal meter - like different light treating or whatever else, I mean, if I was able to "seal" somehow some normal meter - would it work the way I think it should?. Thanks.

I don't know what your setup is likely to be, but typically you will use the cameras lightmeter and compensate accordingly for flash use. That is meter the ambient light for the background and adjust the flash for the foreground expoure, just like you would in a normal shot.

Also the problem with using a "land meter" and sealing it is that the water preassure (even at shallow depths) can make it hard to impossible to operate. So if you are going for a separate meter - use one that is designed for UW-use.

What kind of camera are you planning on using, Nikonos/ Sea & Sea amphibious type of camera or an SLR i a dedicated housing or plastig bag?

Get one of these. I've used it above and below water. It's great.

http://www.ikelite.com/web_pages/digi_meter.html