Macro Flash Calculations

AndrewC · Post by **AndrewC** » Fri Jan 07, 2011 3:44 pm

I don't have a ring flash but if I was running an undiffused flash close up it would probably be down in the 1/25000 range or below. With something like a Nikon SB23 (GN 20) heavily diffused I usually use it in the 60usec range which is about 1/15000.

ChrisR · Post by **ChrisR** » Fri Jan 07, 2011 6:18 pm

I have a feeble ring flash which is quite low power. I hardly use it, but with small effective apertures and heavy diffusion it's flat out, judging by the recycle time. So it might be nearer 1000th, or even a bit longer.
The first thing I did with my woodworking Router was photograph its spinning cutter. Free running they go at about 500 revs per second. 5.5 microseconds per degree!

Harold Gough · Post by **Harold Gough** » Sat Jan 08, 2011 12:33 am

Re: Flash manual output variation.

I have always understood that the power of a new unit (pre-digital era) reaches its full output only after a number of discharges (flashes) and can revert somewhat, temporarily, if not left fully charged when switched off between sessions. This is to do with the storage behaviour of the capacitors.

Harold