spacer brass ring confusion

[chris77]

sounds like a jazz band.

well, i have meanwhile several fine lenses. and yes, it is difficult to not develop an obsession. but thats another story.
the 210 sinaron, which is a apo sironar n selected by sinar i ve heard, came via ebay in excellent condition. it has 2 very slim metal rings between front element and copal1 shutter.
i do also own a 150mm g-claron in copal 0 that came with a single brass ring.

i do have a barrel version of gclaron 150 aswell, no spacer there.
on the internet people say its a direct fit, so with or without?

as i cannot be sure if i have bought originally assembled lenses or not, how can i test it myself? is there a way to visually examine the difference with and without? do spacer rings primarily affect edge sharpness or allover?

regards, chris

[Doremus Scudder]

First, don't lose or confuse your shimming rings!

Lenses are optimized at the factory when installed in shutters for spacing. The distance between lens elements is critical and very small changes can make a big difference (as you can gather from the thinness of the shims). The only really accurate way to determine if and how many shims are necessary is with an optical bench; rather expensive and out-of-reach for most of us. The lenses you have were likely factory-adjusted and shouldn't be tinkered with as regards element spacing.

I'd recommend keeping your lens/shutter combinations as they are.

If you want to test sharpness, keep in mind that whatever you do with a camera will be testing the sharpness of the entire system, i.e., ground glass placement in relation to film plane, etc. Many just focus on and shoot a sheet of newsprint of the like to get an idea of lens performance.

Best,

Doremus

[chris77]

tx doremus. on ebay we cant be sure if lenses are still in their original shutters. i will keep everything as is instead of messing around without the hardware to test.
regards, chris