Joel wrote:
<< Actually Tim the Stofen diffuser is a little rectangular box that slides
into the filter groove, just like yours. For $20.
Do you put a little bend in yours to make it easier to keep in place (as
opposed to cutting it to lie flat)? How many stops do you lose with your
diffuser?
>>
Yes, I had actually seen the Stofen for other flashes. I believe the box
edges are meant to spread the light with slightly less drop off at the
edges, than the normal cos^3 drop off with a flat plate diffuser.
In any case, using the portion of the milk jug near the handle (which is
slightly stippled and thus a little more diffusing) I get about 2/3 stop drop
off with an almost flat (only slightly sprung) plate. With a pronounced
semi-circular plate sticking forward about 12mm (1/2") from the flash the
light drop off increases to about 1 stop. To make the semi-circular piece
you bend the edges sharply so that it can slip under the edge of the flash
when you finally put a gentle curve into the piece and slip it into the
grooves on the flash.
Interestingly the ("bare") GN of the T32 as measured by my Quantum
Calcuflash is substantially lower than Oly's rating and measures the same as
my Vivitar 4600 (using it's fixed 35mm head). Of course this just
illustrates how much more light the T32 puts out since it covers a much
larger 24mm lens. Effectively it has almost twice the light energy output of
the Vivitar or at equivalent area coverage a GN approx 1.4 times larger.
Many of the flashes recommended on the list recently like the Sunpack 555
handle mount unit have more convenient manual power settings and more choice
in non-ttl auto apertures, but their GN's *** at equivalent area coverage ***
are often not significantly different from the T32 or in the case of hot
shoe units (like the 4600) actually have lower GN's. I tested a 555 after
testing the diffuser and it only had a GN one stop faster than the T32 which
translates to about the same GN as the T32 at the 24mm coverage of the T32.
For really high output non-studio flashes you have to go to Sunpak 622 pro or
the very largest Metz units.
Regards,
Tim Hughes
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