In article m,
David Nebenzahl wrote:

Just got finished rebuilding my old Rochester Optical shutter; seems to
be working about as well as it was when new. But I have a few questions
about it, directed to those who know a lot more about these old units
than I.

First of all, let me ID the shutter: it's a pneumatic shutter that says
"R. O. & C. Co/Rochester, N.Y." on the top. On the bottom, on the
aperture scale is "VICTOR". Speeds are 1-2-5-25-100 plus T & B. The lens
says "SYMMETRICAL 5x7" on the side of the front element. Marked
apertures are 8-16-32-64-256 (!!).

My questions:

1. As I said, I think I got this working about as well as it ever did.
The "slow" speeds (those below 1/25) seem extremely dependant on the
condition of the (right-hand) pneumatic cylinder. With the cylinder (&
piston) clean and dry, the speeds are noticeably much too fast. When I
applied a little bit of oil, they slowed down appreciably. Seems as this
is simply a fact of life for these types of shutters; sticky oil, dirt,
or cold weather is likely to have major effects on shutter speeds. Was
the photographer expected to keep his or her shutter "in tune"?

2. Speaking of pneumatic cylinders, the shutter has two, one on each
side. But the one on the left does absolutely nothing! There's even a
hole at the bottom of the cylinder. Were there other models that
actually used both cylinders? If so, perhaps they wanted to keep the
appearance the same, so they kept the left cylinder even though it is
non-functional. Can't think of any other reason to have it there.

3. The operation of the shutter--that is, how the operator uses
it--leaves much to be desired. There's no provision for a cable release.
The same lever is used for cocking (push up) and shutter releasing (push
down). So the only way one would get good results with long exposures
would be if one had a very steady hand (or a massive tripod, or both).

The thing that doesn't seem right is that the shutter doesn't work
correctly unless one keeps the lever held down until the shutter closes.
If you release the shutter but then let go of the lever before the
exposure ends, the shutter will stay open until you press the lever
again. Is this the way these were supposed to work? (I guess I've been
spoiled by modern shutters.)

Don't know anything about these shutters, sounds interesting. I wonder
if a dry lubricant like graphite might be a better choice than oil.

--
Reality is a picture perfected and never looking back.