dunya.nospam@xxxxxxxxxx writes:
<<
You could use a 21mm lens to take some test photos of the flash at each
pullout position. The amount of edge darkness you get when you fire it at a
dark wall would help give you an empirical idea.
>>
This gets innacurate for very wide angles because the drop off goes up very
rapidly off axis for a plane surface for equal intensity per angle from the
flash. To make this uniform on a flat wall for wide angles the flash would
have to put out substantially more at the edges. You need a curved wall
equidiustant from the flash or better use a flashmeter at fixed distance from
the flash and rotate the flash relative to the meter. I have done this by
placing the flash on a tripod and panning the tripod head. This keeps the
distance constant.
Regards,
Tim Hughes
>>Hi100@xxxxxxx<<
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