I recently bought a 240mm f9 APO-Gerogon. It was quite a bargain at $23,
apparently new and unused - it was still in original packaging.
I've fitted it into an Elgeet No. 3X shutter. This is a self-cocking
shutter originally used on an oscilloscope camera. The Elgeet came with
the original 75 mm lens still installed; the 75mm doesn't cover 4x5 so I
seem to have gained a pair of paperweights here. The Elgeet shutter has a
speed range of 1-1/100th second and I use the "T" setting for focussing.
The Gerogon design has the mounting ring it its center with the optical
elements protruding out from both sides of the flange. The metric threads
on this lens did not match the 1.75"-44tpi threads on the shutter so I
chose to mount the shutter at the rear of the lens. Steve Grimes website
has a useful discussion on this type of mounting.
To mount this lens I machined a short lens barrel 1" long and with an
internal diameter a bit over 2", just enough to allow the rear element
group to slide freely into the barrel. The Gerogon required a depth of
7/8" to accomodate the rear element group; the original flange was then
mounted to the end of the barrel.
I machined a short threaded portion on the end of the barrel to screw
into the Elgeet. Interestingly, there seems to be some variation in the
thread dimensions of the Elgeet shutters. The treads which I cut on the
barrel end were a good fit for the shutter which I used and also fit well
into a Graflex Speed-O-Graph shutter which I also have. These threads
were too small for a second Elgeet which I tried - I'd estimate that a
1.77-44tpi male thread will be required when I eventually fit a lens to
the second Elgeet shutter.
I'm using the Gerogon on a older Calumet (C-400?) view camera. There is
no vignetting with the front standard in the full fall position or at
either full slide position. I do see some vignetting with the standard at
full rise (about 2 1/2" on this camera), not unexpected with a rear
shutter. There is a full image at 2" rise and I'm prepared to accept the
1/2" loss of front vertical displacement. I removed the iris from the
Elgeet in order to minimize obstruction of the image path through the
shutter; this is no loss as I'm using the diaphragm in the Gerogon which
of course is already calibrated to the lens.
There probably would be adequate coverage for an 8x10 view camera with
this installation but the movements would be limited.
I've also fitted a 13" f10 APO-Raptar to the Speedi-O-Graph shutter. The
rear elements on this lens protrude 5/8" behind the flange and I was able
to mount the lens in a 3/4" long barrel. The mounting ring threads were
30 tpi , a pitch which I can't cut on the lathe which I use, so I again
mounted the original flange on the end of the barrel. The threads which
mate with the shutter were also 1.75-44tpi.
There is no vignetting evident with the Raptar even with full front
standard rise. I presume that this is a consequence of the greater
prjection distance of the longer focal length Raptar. I left the iris in
the Speedi-O-Graph shutter as it retracted fully into the shutter and did
not present an light path obstruction.
The modest price of the Speedi-O-Graph and Elgeet shutters, $30-50, makes
this type of installation an attractive proposition. The Gerogons also
seem to be available at quite a low price.
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