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Kevin J. Kolosky
16-Apr-2013, 10:24
Many moons ago I purchased a set of cells to make a 210 Sironar N lens. I put them in a shutter and it seems to work well.

But now I see that these lenses were designed to have a very thin spacer ring on the rear cell, which of course mine doesn't have.

Anywhere to get this ring? Or do I really need it?

Leigh
16-Apr-2013, 11:09
Spacers were used when needed to adjust the cell spacing. Usage varies from one specific cell pair to another.

You need an optical bench and some test equipment to determine the proper cell spacing.

- Leigh

Alan Gales
16-Apr-2013, 11:18
You might give SK Grimes a call. I'm sure they can help you. You will probably have to mail the cells and shutter to them so they can determine which spacer you need like Leigh is telling you. Their phone # is 401-762-0857.

IanG
16-Apr-2013, 11:47
It's unlikely your cells need a spacer, of all the lenses I have in their original shutters only my Grandagon has one, it's most critical with wider angle lenses.

Ian

Bob Salomon
16-Apr-2013, 15:35
There isn't a shim. There are several shims available ranging from about 0.5mm to 1.5 mm thick. A particular lens in a particular shutter may not need one, may need one or may need more then one.

john borrelli
16-Apr-2013, 16:19
I wasn't aware that all 210mm Sironar n lenses needed a shim in the rear cell. I have purchased two used 150mm apo sironar n lenses. The first one had two shims between the front cell and the shutter, the second one had one shim between the front cell and shutter.

Leigh
16-Apr-2013, 16:33
I wasn't aware that all 210mm Sironar n lenses needed a shim in the rear cell.
Who said they did???

- Leigh

Sal Santamaura
16-Apr-2013, 16:49
I wasn't aware that all 210mm Sironar n lenses needed a shim in the rear cell...


Who said they did???

- LeighThe OP in post #1. :)

Kevin J. Kolosky
16-Apr-2013, 22:19
I think I will put something real thin in there and see what happens. Thank you everyone.

Jac@stafford.net
16-Apr-2013, 22:50
I think I will put something real thin in there and see what happens. Thank you everyone.

Just unscrew it a bit. Shoot a test. Repeat until improvement or not.

...or instead of making a shot, eyeball it. Do an aerial focus over a ground glass with a center and corner hole more drilled through. Just don't make the hole small enough to cause diffraction. 3/8" will do.

Kevin J. Kolosky
17-Apr-2013, 09:48
I used a small rubber band. Didn't do anything that I could see. I think I will leave it like it is.

Jim Noel
17-Apr-2013, 14:56
An easy thing to try is a shim cut from sheet film. It doesn't even have to be real neat.

Bob Salomon
17-Apr-2013, 16:25
An easy thing to try is a shim cut from sheet film. It doesn't even have to be real neat.

Only works if that is the needed thicness.