[rollei_list] Re: Argomania
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <rollei_list@xxxxxxxxxxxxx>
- Date: Sat, 9 Jan 2010 19:42:56 -0800
----- Original Message -----
From: "Laurence Cuffe" <cuffe@xxxxxxx>
To: <rollei_list@xxxxxxxxxxxxx>
Sent: Saturday, January 09, 2010 2:32 PM
Subject: [rollei_list] Re: Argomania
Have a look at this site and see if anything looks
familiar:
http://www.meggaflash.com/
I have a vested interest, they gave me some bulbs to play
with years ago when I was a poor penniless students.
All the best
Laurence Cuffe
On Saturday, January 09, 2010, at 01:05PM, "Don Williams"
<dwilli10@xxxxxxx> wrote:
These were either General Electric Mazda No.50 or
Wabash (later Sylvania) No.3. Both were intended for use
with "open flash" in studio reflectors. Open flash is where
the shutter is opened manually, the bulb or bulbs flashed
and the shutter then closed. The exposure is long enough to
take the total light output of the lamps. However, the delay
between triggering them and maximum light output was about
30ms so they could be used with an adjusted synchronizer,
for instance, for high speed photography.
Total light output for the General Electric lamp was 110,000
to 125,000 lumen seconds, with a peak of 6 million lumens,
and it is stated that it could be used with a 1/25th second
shutter speed. The Wabash lamp was rated at 140,000 lumen
seconds and peak output of 6 million lumens.
Wabash does not show the light curve but GE does and
the half power points give about a 25ms duration.
Guide numbers are given in my source for GE and Weston
numbers. For the Wabash No.3 is was 560 for 1/25th second
and an ISO speed of about 80. GE gives a guide number of 700
for the same combination. Note that the type of reflector
makes a difference. Differences in the reflectors may
account for the different guide numbers.
These bulbs had about the maximum output available with
flash other than flash powder, which could produce perfectly
enormous amounts of light.
--
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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