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Re: [OM] how to determine light loss from diffuser

Subject: Re: [OM] how to determine light loss from diffuser
From: Winsor Crosby <wincros@xxxxxxxxxxxxx>
Date: Tue, 22 May 2001 11:33:15 -0700
i've made a diffuser using part of a rubbing alcohol bottle, such that it
snapfits into that dovetail thingy on the T32 head/lens. now, i dont have
a flash meter, but i'm guessing i will lose about 2 stops. is there a way to
check exactly how much light is lost by putting similar larger sized piece
in front of a lens and checking the meter? or is that not going to
work? thanks,

/Acer V
--
dum spiro, spero
http://users2.ev1.net/~wesiddiquis/siddiq/      <--!!!NEW LOCATION!!!

Acer,

I am not a flash expert, but I have read several articles that explain that the harshness of light is dependent on the size of the source and its closeness to the subject. If your source is the same size and at the same distance, diffuse or not, there will be little or no difference in the lighting of the subject. A couple of these articles have been illustrated with photos that demonstrate what they say. That is why pros use those big umbrellas and light boxes and put them so close to the subject. The light comes from a wide angle. The best you can hope for with something like that is that light will be deflected to walls and ceiling which will reflect some light onto the subject if the surfaces are near. You might take a more direct approach that would put more of the light on the surfaces that will reflect onto the subject.

Winsor
--
Winsor Crosby
Long Beach, California, USA
mailto:wincros@xxxxxxxxxxx



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