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?
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
If you believe you can, or you believe you can't... you're right.
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.
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
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.
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.
Who said they did???Originally Posted by john borrelli
- Leigh
If you believe you can, or you believe you can't... you're right.
The OP in post #1.
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.
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