What's the strobe's roll in UW Photography?

What is the strobe for? Bringing out color in WA shots? Supplying light which allows me to shoot further? Does certain uw photography not need strobes?

I have a 5050/PT-15. In my very very short time taking uw pics I have so far gotten down adding red back to my pics with photoshop. I planned on experimenting with setting white balance using my slate, but I last dove in Bermuda and did not go deep enough where I had to adjust. So now I am researching what I may need or want next.

Will a strobe capture color in only macro pictures? Would I used it to take scenic shots or of animals more than 2 feet away?

What is the strobes general role?

Thank you

For the macro shots, you'll be fine with your internal strobe/flash. An external strobe will more than likely wash out the photo unless you have the intensity set really really low.

For wide angle shots and shots more than a few feet away, you'll want the strobe to help get a bit of color back into your shots. Intensity will need to be adjusted according to what distance your subject(s) is/are.

I believe they help dissapate some of the backscatter as well.

This is all stuff that I've picked up here in the UW photography forum and can recall by memory. You may want to verify it

I use a strobe on the borrowed setup that I use(roomates cam and friends strobe - LOL). The camera quality is lacking and the adjustability in both the camera and strobe(on the rig I use) have alot to be desired for so I'm pretty sure I'm not reaping the full benefits of the strobe. However, I am getting more colorfull pictures and the backscatter seems to have been reduced slightly compared to when I was simply running the internal strobe. However, I have not used the rig in the same location during the same dive with and without the strobe.

An external strobe is also very valuable in marginal vis, this helps reduce the backscatter. and external strobe will also allow you to try lighting from different angles in order to avoid unwanted shadows or just for a different effect.

Not required in every situation but a strobe is very useful

Ok.
No strobe for macro - internal flash.
Say I take a picture of a wreck, but I back up to get the whole ship in the frame. I am 50 feet away in gin. Will the strobe have an effect on that pucture.
If I need to be about 2 feet or less to get a good pic with the internal strobe, in clear water what distance deems a strobe useless?

It won't do anything at all at 50 ft!
Your internal flash is OK for macro as you are so close to the subject that there aren't so many particles between the lens and the subject. If you come out to 4 - 8 feet particles in the water become more problematic. In that case your internal flash will reflect straight back to your lens giving backscatter. A strobe is mounted much further away from the lens so the angle is greater. With correct positioning the light bouncing back from the strobe will not hit your lens - so less backscatter.
The effective distance that a strobe will reach depends on how powerful it is. Personally I wouldn't think any strobes are much use beyond 8ft or so. 3 - 6ft is probably the main useful range. If you use a strobe with the C5050 then it's better to block the light from the internal flash. The Inon D180 comes with special blocking filters that you put over the internal flash - it blocks visible light - but allows non-visible light through. This is important as the strobe has to synch with the internal flash - but only needs non-visible light to do that.

just think 3 to 5 ft

anything past that turn off any flash you are using

Kim is on the money, even when I use dual 400 watt flame throwers, 6 to 8 ft ( depending on aperture ) is max.

Chris -
Have you ever thought about using these HID lights that cavers use? I know that they are very expensive but they seem to throw light a very long way. I must admit I'm a bit curious!! I believe with some of them you can vary the beam width as well.

I recently worked with the Deep Sea detectives crew on Guam, they had some intense HID lights, Dual 50 wt, with 6 inch reflector, very wide coverage and quite bright. but I think that is not going to be effective unless used on still objects with a tripod and long exposure times. Strobe intensity in "watt seconds" is much brighter but is only thousands of a second in duration. in reality the only way to increase the distance would be to increase the duration of the flash, but that is quite difficult due to the heat build up it would produce.

not to mention that was a $5000 set of lights!

Kim, my experience is that exceeding 10 to 12 feet of water for total light path (strobe to subject + subject to camera) results in colors that become noticeably blue.

A good example is the blue faces you get at the bottom of a swimming pool. This is daylight filtered through water, the total light path about 10' (surface to subject + subject to camera).

I have often used big horsepower strobes with wrecks to kick a little bit of light into shadows, with distances up to 20'-25' perhaps, with the foreknowledge that the return color will be bluish. A specialty application, to be sure.

Strobes are a close approximation to daylight. HID and halogen are different color mixes that require you to white balance for that light source. You'll still end up with the 10' blues, though, and a spotty lighting pattern to boot.

I can manufacture a red channel from scratch, too, but it isn't the real thing. Human flesh tones are especially hard to balance. There's a reason that serious underwater photographers carry as much poundage in strobes as they carry in housings!

What Chris says is exactly right, keep it close. When I shoot wide angle of someone that isn't familiar with it, they invariably think I'm waaayyy too close.

All the best, James