I have never seen another one of these
successfully installed into a useable photo shutter, although these lenses
are almost common military surplus.
The curves of the glass are very steep.
An Ilex #4 shutter turned out to have its iris and main blades
close enough together to allow the nearly ball shaped front and back groups
to be gotten to the correct close spacing as in the original camera mount.
It was also necessary to enlarge and re-thread both front and back of the
shutter as well as turn down and thread each cell mounting group.
The lens is a symmetrical design and the back cell exhibits the same
radical curves. It projects beyond its mount and care must be taken to
not damage it accidentally.
Besides enlarging the front and back mounting threads it was necessary
to remove the spring loaded friction base for the iris control in order
to get the back element close up to the iris. This reveals the axle
points of the iris blades, usually hidden but the base metal of the
large back element replaces the friction plate perfectly so the iris
operates normally.
Because the front group is very large and fits nearly up
against the front of the shutter a cutout is made to allow viewing of the
selected shutter speed from the front.
Similarly, the iris is engraved on the side of the shutter
after shortening the original iris control to a "pointer"
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S.K. GRIMES
