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Re: [OM] More Calcs on Flash GN

Subject: Re: [OM] More Calcs on Flash GN
From: HI100@xxxxxxx
Date: Wed, 8 Mar 2000 18:05:34 EST
Rand E. commented :
The area where we part is that all your data is factory given (optimistic ?) It 
is a well
presented design concept.  Has anyone tried this with "actual" data ? 
What are the results ? 

I was just interested in comparing conversion efficiency of the different 
flashes assuming that the manufacturers numbers might be optimistic but should 
at least be self consistent. i.e. The optimistic bias would be the same for 
different flash models from the same vendor. 

I actually did do some measurements with OM,Vivitar and Sunpak flashes using a 
flashmeter on axis at 2m a while back. I don't have the numbers in front of me 
but as expected with dark surroundings no white walls etc the GN's were much 
lower than the vendors specs but were reasonably consistent from one vendor to 
another (surprise!). i.e. They were using similar optimistic fudge factors.

>From my perspective the interesting aspect (as pointed out in my amended 
>post),is the T20 is considerably less efficient than the T32. My memory is 
>that the Sunpak was a bit less efficient than the T32 as well since the 544 I 
>tested is the same Energy rating (70J) as the T32.

         >> Tim Hughes <<

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