Best positioning for strobe to reduce backscatter

[MauiScubaSteve]

To keep this going because it is fun. My take is that all DSLR have made their way into photographers hands and that the total number of DSLR cameras made so far is about 54 million (12 million last year alone). If 2 % of those got into UW photographers hands, that is about 1 million or so. To me that is many. If it is only 1% then it is half a million and that still is many. Many is one of those interesting words that has no relationship to percent (unlike most say) and is perfectly context driven. If I do an experiment with 40 rats I would say that many of them had a particular outcome if it was 25 or so. In any case my estimate of total number of underwater housings for digital cameras is several million with DSLR maybe 15 % of the total, still to me many, but maybe not to everyone.
Bill

Sorry Jak Crow; hope you are having fun too!

Bill, I think you are way too generous with your use of the term "photographer." The way I define photographer eliminates at least 90% of today's purchasers. I have had periods where surface photography was my focus; especially the three years in the Monterey Bay area

:cold:

Back in the late 90's my "whale watch" rig was a Canon 10S w/ Canon L 35-350 mm, "sorta" upgraded in the early 00's to Canon 1N w/ Sigma 50-500 mm and last year I inherited mom's "backup body" (Canon 20D), so I am one of the U/W photographers a dSLR is in the hands of, but I've never been interested in taking any of those "bodies" underwater.

Several million dSLR housings going into the water seems really hard to believe, even counting "surf photographers" who use no strobes at all. Now that I think about surf, wave, kayak and whale photography, I'm pretty sure there are more no strobe housed dSLR's here than strobed housed dSLR's. It seems that finding out the total number of major manufacturer dSLR housings sold would be easier than finding out the total number of major agency divers certified; is this "fun enough" for anyone to give that exercise a real try?

 

[bvanant]

The cone angle reported by most manufacturers is dependent on how you measure. Inon says circular beam at 110 degrees with diffuser. The YS110a says 105 degrees with diffuser but the amount of light at 45 degrees for these two strobes is decidedly different. Is 110 degrees where no more light is available? or is it 2 or 3 stops below the center of the beam?

You have to test it for yourself I think.
Bill

 

[bvanant]

Several million dSLR housings going into the water seems really hard to believe, even counting "surf photographers" who use no strobes at all.
I too think that several million seems high but I was using your 2% number. I have tried quite diligently to find out how manyDSLR and other interchangeable lens camera housings have been sold with little success. Most of the housing companies are private and don't publish annual reports. In any case even if it is half a million that to me would be many. Finally to get to the original poster's point, I don't think most DSLR shooters who shoot with 2 strobes do so for backscatter reasons.

Bill

 

[ScubaJohn65]

Statistics and Scuba Diving ... Within the US, about 1% of the population participates in scuba diving. Probably more than 1/2 of all divers in the or from the US have put some type of camera in the water to take pictures. I'm a little "old-school" and don't really consider every diver who puts a some type of camera in the water as an U/W Photographer, but simply a diver taking pictures to hopefully share with the other 99% who haven't yet experienced the Underwater World for themselves. Some one who has a serious interest in taking quality U/W Images and uses pro-sumer to professional level equipment to capture those images is an U/W Photographer. I won't put the "d" in dSLR as a restriction since some old-schoolers might still be using film. I shot my first U/W images using a Nikonos V 35mm lens with a single strobe in 1989. 36 pictures and wait to see your results - a hard way to improve the quality of your underwater images.
After taking a roll of film pictures in Monterey, I went to 2 strobes.
Now, since most of my dives involve taking others diving, I rarely have the opportunity to put my camera in the water. As such, when I do, I use a simple point-n-shoot with a diffuser over the internal camera flash. I'm now taking pictures underwater to share on social media sites and to use in marketing flyers - not to make big prints to hang ont the wall.

 

[mjh]

As to strobe positioning this may help: http://opticaloceansales.com/files/Strobe Positioning-sm.pdf

As to people out there with cameras, tough to calculate. A very popular housing maker estimates they will sell about 800-1000 of the new Nikon D800 housings world wide. Another popular resort that does exit surveys reported +60% of their guests had some form of camera. So think of all the camera models, housing manufacturers, people still diving their Nikonoses.....

 

[dpaustex]

Well, my dSLR goes underwater...

As for strobes, and backscatter, you have to understand the old "angle of incidence" and "angle of refraction" rules. Basically, you're tyring to get light to the subject in such a manner that the stuff in the way is hit in such a manner as to not "show up" in the photo, due to direct reflection into the lens, and onto the sensor. Doesn't mean the stuff isn't in the water, you're just trying to minimize the effect.

I used to use a Canon G-9, which has a built in flash. Fairly useless until I started using an external flash on an arm (then 2).

Above all, you need to play with your setup on dry land, first, to see what kind of shots and lighting you are getting. If your flashes have TTL abilities, all the better.

I would encourage you to simply stick with it, take lots of shots, then ask for input on what is wrong, if they are not to your liking.

Photography starts with the light...and ends there, too. Get the lighting right, first, then you can work on composition.

This is most easily done by strobes as far away from the lens as possible, and trying to slightly overlap the light cones projected by the strobes (see the mfr's data sheet), such that the light "edges" overlap your subject (somewhat ignore this advice for true macro).