How to properly fit a SSXL into a new shutter?

[Michael Nagl]

I killed the shutter of my 150mm SSXL yesterday (just don't ask how, please), so when I was out today I screwed the cells into the shutter of another lens and hey that lens did behave in a strange manner. Weird curvature of field or something of the kind I guess. Well, when I came home I measured the lens, first in it's original shutter, then in the other one, in which it was about one millimetre longer, and surely that's not irrelevant. So here's my question: What can I do - other than sending the lens to Schneider, wait for a few weeks, pay 300 Euros, and dump the spare shutter I have already paid for at the *bay?

Thanks for advice
Michael

[Gene McCluney]

Sounds like you have the plan. Lens spacing is probably very critical.

[Ernest Purdum]

It's quite puzzling that there would be a whole millimeter difference between the two shutters. What are the two?

[rob]

This is a dumb question: Did you notice a shim stick to the shutter mount?

[David Lindquist]

This from the Schneider website suggests that with the SSXL's, spacing is particularly critical:

"If, for some reason, the shutter has to be
replaced, this must be done only at the
factory, because the tolerances which the
shutter has must be replaced by a new
precise calibration. For just as a Formula-¡
race car tuned for the highest perform-
ance responds more sensitively to “sand in
the gears” than a tractor, so does the
Super-Symmar XL Aspheric react more
sensitively to deficient adjustment in con-
nection with installation in the shutter
than a more simply constructed lens."

Now my 120 SSHM has a very thin shim between the front component and the shutter, suggesting shimming with this series was also resorted too. On the other hand my 110mm SSXL doesn't seem to have a shim (I didn't want to unscrew the front completely when checking this). My guesses and hunches on this: Schneider tests each SSXL for proper spacing when mounted in its shutter (anyone know if this is the case and how they do this?) and in some cases the spacing will turn out to be "just right" without a shim. And presumably only the front component gets shimmed since you have to remove the back component to mount the lens on a board.

Having said this, a difference of 1 mm in overall lens length between the two shutters seems quite gross, I'm assuming here both are Copals.

There was a discussion of shimming on this forum (or maybe it was APUG) a while ago.
David

[Bob Salomon]

To properly do it you send it to Schneider. Second choice would be to send it to a highly qualified repair center. Last and worse choice is to do it yourself.

Since you have purchased the shutter you could send it along with the lens. Or just resell it yourself.

[Michael Nagl]

The original shutter was a Copal, the other one is an old Compur electronic; note that the overall length of the lens is longer in the Compur. If there is a shim in this shutter it's well hidden.

[Bob Salomon]

The original shutter was a Copal, the other one is an old Compur electronic; note that the overall length of the lens is longer in the Compur. If there is a shim in this shutter it's well hidden.

The Compur Electronic 1 with a 150mm Sironar had a flange focal length of 142mm while the same lens in a Copal 0 had a flange focal length of 143mm. The overall length of the lens in either shutter was 55.5mm. The distance from the rear of the shutter seating to the rear of the lens with with Compur Electronic 1 was 18mm and with the Copal it was 19mm.

So these two shutters are not the same dimensionally. As you noted there is a 1mm difference physically but there is also a 1mm difference with the 150 Sironar in flange focal length with the Electronic requiring the shorter distance.

Additionally your lens is much newer then the Compur Electronic so the shutter was never made to accommodate that lens.

This is a job for a specialist.

[Bob Salomon]

The original shutter was a Copal, the other one is an old Compur electronic; note that the overall length of the lens is longer in the Compur. If there is a shim in this shutter it's well hidden.

Another measurement that might help you is on the Compur Electronic - m 0 and 1 shutters the distance from the front and rear faces of the opening were 20mm +0.004mm.

These are exactly the same measurements as the Compur 0 and the Compur 1 had and
the Copal should be the same.

[Michael Nagl]

Thanks a lot Bob. The Compur electronic was at hand today, but I was planning to eventually replace the dead shutter with a mechanical Compur that is yet to arrive. But - that was when I was still young and naive.