Using three or four camera mounted strobes...

I can see that using multiple strobes (three or more) may provide an eveness of foreground lighting or a 'projected' evenness of fore and mid ground lighting to w/a images but I wondered what experience fellow WP's can throw on this art? I have access to six Z-240's and when I've settled into a 7D its a project which is starting to fascinate me...

Generally multi-strobe set ups (more than 2) are for those who do not know how to use two! I have heard on quite a few occasions people claiming they need a third central strobe for their standard wide angle shots, but almost always this is because they are not aiming the two they have got well enough. A well set up three strobe rig will give good results - and many people have found it has helped their images, but I think that has more to do with them not using two strobes well, then three being the solution. I just do not see the 3 or 4 strobe shots that I have seen being any better than I see good wide angle shooters getting with 2 strobes.

Maybe it is like putting stabilisers on a bicycle. Yes, with four wheels a bicycle is more stable...

That said multi-strobe set ups do have some benefits for getting shots that would be tough with 2 strobes. But these are rarely discussed. The main use I have for three strobe setup is for mega-large scenics - lighting up very large sections of reef with your strobes. For this you need the coverage and power only possible by increasing the number of strobes (especially if balancing with strong tropical light). These examples here are really large scenes (lit with three strobes) - personally I do not like them as images - but as a technical exercise they were interesting:

There is no scale in these photos, but these are both really large sections of reef.

The other creative advantage of multi strobe set-ups is fast recycle time as all the strobes can be on low power and therefore allow you to shoot many frames a second. There would also be a creative advantage in short flash duration (a full power flash takes longer to fire than a low power one) - which could be useful for stopping fast action (although I can't think of anyone doing this underwater).

Regarding the wide angle use - if you want soft, even light - you probably want some big wide angle strobes (Ikelite, Seacam, Subtronic etc) rather than endless Inons.

Alex

Thanks Alex.

So it all comes down to recycling speed then? So what fps would you expect from from a four (Z-240) strobe setup when compared with a two strobe? I'm thinking here about open water pelagic shots.

That aside, I remember well your advice about high reach strobes (and high ISO) giving far illumination in wreck shots (the Thistlegorm). I wonder whether low strobes in addition to the high reach strobes may benefit those shots?

Many thanks, Tim

So it all comes down to recycling speed then? So what fps would you expect from from a four (Z-240) strobe setup when compared with a two strobe? I'm thinking here about open water pelagic shots.

I think you will be able to shoot 3-4 frames a second, no problem. Maybe more, especially with an ISO bump. So then I guess that the camera synch speed is the main limitation - you need a fast shutter speed to get the max FPS.

Alex

Another way of using 3 or more strobes creatively would be to use different color filters on each or by balancing strobes with different warmths. Tony Wu had an interesting article about shooting Lionfish in PNG were he used two warm Ikelites to light the reef and lionfish from below and a single handheld Inon or Sea&Sea from above that added a really nice blue fill on top...

Generally multi-strobe set ups (more than 2) are for those who do not know how to use two!

I think this is a little harsh, as you yourself say there are uses for more than 2 strobes. If people want to use more strobes because they find it easier or want to experiment, more power to them.

The 2 reasons you mentioned (lighting larger scenics and being able to use lower power) is mainly why I sometimes add a third strobe on wide angle dives (like recently in Eastern Fields). My YS110s have like a 10 minute recycle time, but just putting it on -1 lets me shoot several shots in a row. A third strobe makes that possible. Especially when you have a subject (like a big grouper) that is bound to be doing stuff just while my strobes are recycling.

Looking at Z240's now, at least their recycle time is a little better

To get a very high FPS one will have to dial down the strobe quite a bit. Do a simple test by dry-firing and checking the histograms. If the FPS is too high the first histogram will be different (indicating more exposure) compared to subsequent ones, which may all look quite similar.

I have done this test with the housing on the floor in my living room using my remote control and keeping my eye on the chimping screen. This insures that the camera does not move between shots, which must be identical for a valid test.