[LargeFormat] Wollensak Rapax Shutter

[Richard Knoppow]

  Until the other day I thought the Rapax, also sold as the 
Graphex, originated after WW-2. It turns out that it 
probably was first made about 1942 or 43, not long after the 
Kodak Supermatic. The first Rapax/Graphex shutters evidently 
had brushed chrome faceplates rather than the black ones 
familiar to me. Graphex was a trade name used by Folmer 
Graflex for shutters sold on Speed Graphic cameras. From the 
advertising I just noticed the first shutters were the small 
sized ones used for 101mm lenses.
   I wonder if anyone on this list has one or has seen one. 
At the time this shutter first came out Wollensak was still 
using Velostigmat as the trade name for its best lenses. 
Like Ektar, Velostigmat, and the later Raptar, specified a 
quality of lens rather than a generic type.
   Rapax/Graphex shutters are good ones. Their advantage 
over the Supermatic and Compur is that the force necessary 
to trip the shutter is low and constant at all speeds. This 
is important where a solenoid is used for flash 
synchronization. Both the Supermatic and Compur require 
rather higher pressure for tripping at the highest speed. 
Unless booster batteries are used the solenoid may not trip 
them at all at this speed. Also, the pressure is great 
enough even at slower speeds to cause unreliable operation 
of the solenoid unless either an extra battery is used or 
one uses the special higher voltage dry cells sold at the 
time for photo-flash use.
   I am especially curious if anyone has both the 
Velostigmat and Raptar/Optar versions of the lenses sold for 
Speed Graphic use. My experiencew with post war Raptar 
lenses is that they have a design flaw resulting is blurry 
images in the corners and margins even when stopped down to 
minimum despite being very sharp in the center. I am 
wondering if the design of the lens was changed c.1946 or if 
the older versions also have this problem.

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Richard Knoppow
Los Angeles, CA, USA
dickburk at ix.netcom.com