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[OM] Re: T.Power Control labels (was Re: Last of OM items for sale)

Subject: [OM] Re: T.Power Control labels (was Re: Last of OM items for sale)
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
Date: Fri, 20 Jul 2007 07:41:52 -0400
If the available energy to each head is cut in half (1 stop) then the 
guide number would nominally be reduced by the square root of 2. 
Dividing 28 by 1.4 I get 20 instead of 22.  But I guess that's close enough.

Chuck Norcutt

Jeff Keller wrote:
> The guide number is limited by the energy stored in the capacitors
> and the width of field illuminated. If two heads are sharing the same
>  energy it seems reasonable that the guide no. would go down ... 
> -jeff
> 
> On 7/19/07, usher99@xxxxxxx <usher99@xxxxxxx> wrote:
>> Piers, Thanks again for these.?
>> 
>> Weird that on the Alan Wood site in one place near where he
>> mentions the calculator panels (T28), the? GN with one flash is
>> listed as 22 and 28 with 2 heads.? It is the opposite later on his
>> site and anywhere else, including on your panel pdf.?? Must be a
>> mistake on the AW site.? I don't know how the GN would go down with
>> 2 heads (must be the case), unless the controller T power control
>> attenuates the power to both.? Perhaps there is something weird
>> about GN's at macro distances.? Manual macro flash shouldn't be as
>> weird as quantum effects, though Heisenberg seems to lurk over my
>> shoulder when I try it.
>> 
>> http://www.alanwood.net/photography/olympus/t28-macro-twin-flash.html
>> 
>> 
>> Mike
> 
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