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| p.1 #3 · Critique and OCF Hints? |
Your shots turned out well.
The simple way I learned to do lighting ratios with dual flash back in the day when flashes only had one manual power was to use two identical powered flashes, one on bracket as fill and the other off camera as key light. That way if you put your OCF at the same distance as your camera fill you automatically get a 2:1 reflected ratio:
1:1 Fill over the camera lights entire face with nearly shadowless fill
1:0 Key light at same distance / strength overlaps fill
2:1 Reflected ratio is 2:1 — highlights reflect 2x more light than shadows
Figuring out exposure is simply a matter of doing some testing at various shooting distances. For example, once you find what power / aperture you need for correct exposure at 8ft it will always be the same when you shoot from 8ft.
Getting a stronger ratio (i.e. same highlights / darker shadows) requires putting your key light closer than the fill (assuming they are identical). If for example you are shooting at 8ft with fill at that distance, if you move the OCF in to 5-1/2 feet it will be 2x (1 stop) stronger and your ratio will be 3:1
1:1 Fill over the camera lights at 8ft. entire face with nearly shadowless fill
2:0 Key light at 5-1/2 ft is 2x brighter
3:1 Reflected ratio is 3:1 — highlights reflect 2x more light than shadows
Again its just a matter of testing (or chimping highlight clipping in playback) to zero in on the correct exposure. I still use that 3:1 method when shooting portraits with my pair of 580ex flashes because its predictable and foolproof.