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Elimination of backscatter


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#1 seansrs968

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Posted 28 August 2012 - 08:20 PM

Anyone have any suggestions on how to elimante backscatter in photos besides moving the arms wide apart and not shooting on full power? The reason I ask is that I live here in southern California. It seems even when we have great conditions there is a lot of particilate in the water and I seem to get a lot of it in my photos :(. Would love to hear any suggestions.

Thanks,

Sean

#2 Stitchercaroline

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Posted 29 August 2012 - 08:19 AM

Hi,

Have you tried lighting the subject using the edge of the beam? Strobes pointing straight or slightly outwards and use the innermost egde of the beam, rather than pointing the strobes directly at the subject. Found out about it by reading a book by underwater photographer Martin Edge.

Good luck!

Caroline

#3 tdpriest

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Posted 02 September 2012 - 02:56 PM

Have a look at Martin Edge's The Underwater Photographer, for advice on this fundamental aspect of underwater photography...

... as Caroline says. It's all about angles, not really about long arms and low power at all. Oh: practice, too...

#4 Alastair

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Posted 07 September 2012 - 10:52 PM

here in the UAE we have ppor water conditions and a lot of particles in the water. but i still manage to use WA on occasion. my main methods are to firstly get very close. My strobes pointing out and i try and avoid the sun in the photo unless it is at the right angle and can be put in the corners or i can hide it behind something (coral head for example) other wise it seems that i have too much particulate matter lit by flash and sunlight.

good luck!!
Alastair

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#5 Herb Segars

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Posted 08 September 2012 - 09:25 AM

Sean:

Here is something that works for me. I try to match the available light in my exposures. One of the reasons that backscatter is so noticeable is that it is brighter than
the surrounding water. The brighter the background, the less noticeable the backscatter. In the photo below, the visibility was at the most 15 feet. You can see that there is backscatter in the photo but it is less noticeable because the available light is as bright as it is. If I had used a smaller fstop or a lower ISO, the background would have been darker and the backscatter would be more noticeable. I agree with other suggestions of edge lighting, etc. but when I am shooting with a wide angle lens in turbid water, employing those techniques with matching available light has worked well for me.

Posted Image


I will usually start by setting a lens opening (f8, f9, f10 or f11) and a shutter speed (1/30th second). I then meter the water towards the surface (not directly at the sun) and adjust my ISO setting to center my in-camera light meter. I will then adjust the power of my dual Ikelite DS-125's to a power setting based on my distance to the subject. Usually, I am using 1/4 power. The shot above was more difficult than most because the area under the stern of this tug was pretty dark. I needed to aim my strobes inward to light the prop. If the background had been one or two stops underexposed, the backscatter would really stand out. The photo was taken with a Tokina 10-17mm lens at 10mm, an ISO of 640, a lens opening of f9 and a shutter speed of 1/30th second.

Here is another shot taken in visibility of around 15 feet or less. This was easier because I was shooting a tugboat on an artificial reef off New Jersey. You can see the backscatter in the lower part of the photo where it is dark but not so in the mid and upper part where I have matched the available light.

Posted Image


This photo was taken with a Tokina 10-17mm lens at 11mm with an ISO of 640, a lens opening of f9 and a shutter speed of 1/30th second. Both photos were shot in Manual mode.
Herb Segars
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