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[OM] T series vs METZ Flash

Subject: [OM] T series vs METZ Flash
From: HI100@xxxxxxx
Date: Sat, 29 Dec 2001 15:04:54 EST
Cc: jlind@xxxxxxxxxxxx
In a review of the Metz flashes John L wrote:
>>
The more powerful big brother is the 60CT-4 
with a whopping GN of 197.  This is more flash power than any of the 
Olympus "T" series and is almost the equivalent of 4 T-32's!
<<
Not really, GN's confuse the issue when the lens angle covered is different.
If you take into account the different angle of coverage, the T45 has only 
slightly lower total light output than the 60CT.
If the light of the 60 were spread to cover the same area as a 24mm lens, 
(that the T45 is capable of covering) the 60 would only have a GN of 157 (in 
ft) versus the T45's GN of 147 (in ft). 
*** In a way the T45 has one of the highest light ouputs of any handle mount 
flash with an integrated battery pack, given the angle of coverage is so 
wide.*** Most flashes give guide numbers for a 35mm lens (eg Sunpak622) or 
28mm lens for more pro oriented flashes (like Metz CT60). The T32 and T45 are 
unusually wide (24mm) making them look less powerful. The Contax RTF 540 
potato masher flash with seperate battery pack also covers a wider angle. 

The common wisdom on the list is the T45 is two T32's in the same case. This 
is a bit simplistic. The T45 does have two flash tubes and two flash quench 
circuits. But it shares a single trigger circuit and light sensor circuit. It 
also shares one voltage control feedback circuit for the invertors, but it 
has five seperate voltage invertors running off five seperate 4 cell Nicd 
batteries. Using five invertors running of Ni-cd's greatly accelerates the 
recycle time on the T45 (~2sec vs the T32 ~8sec)

The following Olympus patents seem to cover the T45 concepts (check USPTO 
website) :
US4530034 (T45 multi battery ccts, multiple invertors,feedback) etc
USD0283331  (T45 case design)

                  Regards,
                 Tim Hughes
                >>Hi100@xxxxxxx<<

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