3:54pm, 8 February 2010
I have been trying to make a read out of the power, that between 10 - 60 what will be the exact Fstop. Could anyone give an answer for my question please?
dcrane1000 8 years ago
The 10-60 scale is about 5 stops. Each increment is supposed to be about a .10 stop, but seems to be closer to .09 based on the testing referred to in the Strobist flicker group. You can do a search over there to see the original references.

Of course your best bet would be to test it with your own flash meter. Let us know what you learn! 8 years ago
Will do, thanks. But to be honest, I do not really meter my flash, mostly use it like a "wysiwyg" , I mean set the power as I see/want it.
photopath PRO Posted 8 years ago. Edited by photopath (member) 8 years ago
These are the exposures I get with the flash meter 1 metre from the centre of my softbox

Genesis 200 / Illuma Medium /1 metre / 200 ISO

Power F stop (above stop)
10 4 (0.4)
15 5.6 (0.1)
20 5.6 (0.7)
25 8 (0.2)
30 8 (0.7)
35 11 (0.1)
40 11 (0.4)
45 11 (0.7)
50 16 (0.0)
55 16 (0.3)
60 16 (0.5)

Or, adjusting the power to give full stops I get

F stop Power
f5.6 14
f8 23
f11 34
f16 50

So it gives a measured range of just over 4 stops

Sorry - flickr removes the table formatting!
photopath PRO 8 years ago
"....mostly use it like a "wysiwyg" , I mean set the power as I see/want it. "

In which case - you didn't really need to ask the question........ 8 years ago
Yep, but wanted to ask and see how it is properly. But thank you for the answer, already printed out these settings and put it onto the wall, thank you
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