Ian wrote:
> to be adjusted in view of the film speed. So if I have a flash with a
> guide number of 20 (ISO 100 in m) and I'm using ISO 400 film, I should
> use a guide number setting of 40 (m). Is that right? I quickly
Correct, the Guide Number takes account of the film speed. For a set flash
output you can calculate the Guide Number for a different film speed as:
GN = ISO100GN*SQRT(ISO/100)
Wayne Harridge
Ivanhoe, Victoria, Australia
http://members.optusnet.com.au/~w_harridge/
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