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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