Am I getting that much backscatter from the main flash? I do have a lot of backscatter; I just thought it was mainly from the strobe, since my reflector sits right in front of the main flash.
backscatter when using internal flash to trigger a slave flash?
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By main flash, do you mean your camera's built-in internal flash? If so, yes. Any strobe or flash that is fixed or pointed straight out in front of the camera will produce backscatter. The light is thrown straight out and bounces straight back into the camera lens off particles in the water as well as your subject.
By using an external strobe, you can aim it at an angle to the subject so that same light is bounced off at an angle, not directly back to the lens. Sort of like shining a flashlight in a mirror. Make sense?
By using an external strobe, you can aim it at an angle to the subject so that same light is bounced off at an angle, not directly back to the lens. Sort of like shining a flashlight in a mirror. Make sense?
That does make sense. But the main flash on mine has a black plastic piece in front of the camera flash, which reflects up to the strobe. From what I gather, that isn't sufficient-that I need to completely block that flash? And I can do that with duct tape, which allows the IR signature to go through, but blocks visible light, or I can do that by taping a tube or fiber optic between the sensor and main flash?
miketsp
Contributor
I find it hard to believe that duct tape will let IR through.
Just came back from diving-I didn't have duct tape available, but used some medical "paper" tape instead. It worked fine on the surface, but the strobe wouldn't fire underwater.
How do I rig up a clear tube?
How do I rig up a clear tube?
FWIW - with the two Canon A series I have I did not get a backscatter problem from the camera's internal flash when using an external strobe. I did not cover the internal flash with anything.
Hollywoodivers
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alcina:
Gotta get closer to your subject and cover the internal flash or get a fiber optic sensor so that that flash can be totally covered and still fire the flash ...see the sea and sea ys 25...is your housing clear ? You may be getting some unwanted light through that housing...good luck
Hollywoodivers:
Are you sure you meant to quote me? I think maybe you meant to quote whitedragon?
My post was to offer an alternative position as I have had no problems with my A70 or A20 without covering the internal flash. I have used the Ike 50 with slave controller and the Inon 220s with fibre optic cable. There are example of all three strobe set-ups (Ike, Inon and internal only) in my gallery.
Have been using these systems for more than two years - both myself and students/clients with no experience to lots of experience in uw photography.
whitedragon13:
So your strobe is working as a slave off the reflected light of the internal flash? There's no connection between the two? Does your camera have a pre-flash? If so, is your strobe designed to work with it?
I've never heard of a di-it-yourself fix with duct tape!
the only other thing I can think of is your strobe is facing straight out from the image plane, reflecting straight back into the camera.
Using any strobe in any configuration with any camera rig is no guarantee to eliminate all backscatter.
Here's what my rig looks like, with a different camera.
Sealife Camera
The black plastic in front of the main flash has a reflective sticker on it, which triggers the strobe.
Not sure what you mean by "preflash". The camera has an external strobe setting, which fires the main flash a couple times before the strobe fires.
Sealife Camera
The black plastic in front of the main flash has a reflective sticker on it, which triggers the strobe.
Not sure what you mean by "preflash". The camera has an external strobe setting, which fires the main flash a couple times before the strobe fires.
