[LargeFormat] Wollensak Rapax Shutter
Richard Knoppow
dickburk at ix.netcom.com
Fri Nov 18 18:17:12 EST 2005
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.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk at ix.netcom.com
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