Any Schneider 210XL owners here?

[David Lindquist]

I think that the rear asphere in these is correcting a lot of aberration from the front group. Hence the tolerance in positioning of the two sections relative to each other is likely much tighter than some earlier lenses.

Yes T.C. I can believe that the lens shims are thin, might be a 'thou' or slightly more, to make a useful step in the air gap.
I spoke to Schneider about my Componon-S 210 a few weeks ago and they warned me to look out for a shim when I took it apart to alter the mount. It didn't have one, but they said some have one, some don't.

In addition to the examples of new lenses, shimmed and not, that I cited above, I did find a used 55 mm Apo-Grandagon to have a shim .012 inches (about 0.3 mm) thick (measured with dial calipers.) . The shim on my 120 mm Super Symmar HM seemed rather thinner, delicate to the point I'd rather not risk handling and measuring it.

David

[Lachlan 717]

So much written here about shims…

You will NOT see any difference, whether shims are there or not, on a ground glass.

This is something else.

[Mark J]

Of course it is. This is about fine-tuning the performance, for example what sharpness you get on a 55 Grandagon at f/11.
If you read the front page of Schneider's patent for the last Apo Symmars ( c.1998) , you see that the stated aim was to improve the lens again by an increment to match the performance of the best contemporary film stocks and allow use at f/11 and f/16 to minimise diffraction.
It would only be of real importance to some people doing product shots or billboards, but that's the reason for the additional consideration of tolerances.

[Lachlan 717]

Of course it is. This is about fine-tuning the performance, for example what sharpness you get on a 55 Grandagon at f/11.
If you read the front page of Schneider's patent for the last Apo Symmars ( c.1998) , you see that the stated aim was to improve the lens again by an increment to match the performance of the best contemporary film stocks and allow use at f/11 and f/16 to minimise diffraction.
It would only be of real importance to some people doing product shots or billboards, but that's the reason for the additional consideration of tolerances.

Maybe on 25asa film shooting line pairs, but not on a ground glass (with its 25000asa gritty surface).

You will never see the difference on the GG of shim vs no shim.

[Mark J]

Erm, yes but there's lots of stuff you will not see on the ground glass that you do see on a print. Not everyone shoots 7x17 !

[Lachlan 717]

Erm, yes but there's lots of stuff you will not see on the ground glass that you do see on a print. Not everyone shoots 7x17 !

It’s got nothing to do with format.

It has to do with process/testing methodology.

You wouldn’t test a digital lens’ sharpness by shooting fine detail at highest ISO. So, to, you can’t gauge this lens’ sharpness by looking at a GG. The very nature of a GG is that it needs a (varying) level of coarseness to allow the image to appear. It will act as a soft focus screen in order to preview the image.

Whether 7x17 or 2x3, this will not change.

Finally, there has been no response to whether the lens is torquing the front mount out of parallel that I proposed earlier. That will give a demonstrable effect on a GG.

[konakoa]

Lachlan, the camera for now I'm evaluating the lens on is a metal monorail. I've watched the front standard as I insert the 210XL lens. As I let go of the lens and the weight transfers fully to the camera I haven't noted any flex on the standard. Currently I'm exposing a few negatives with the rear element fully seated, then loosened one revolution where I did see a difference in the 12x loupe on the ground glass. Weather now is not great with high winds, rain and freezing wind so I'm waiting on an opportunity to finish up the film checks with the lens.

[John Layton]

Question relating to shims (or lack thereof) and testing: If one purchases a used lens and then notes that it comes without shims and also shows a level of performance not "up to par," who can one send this to for both testing and the installation of the correct shim?

[Tin Can]

I use a Horseman Optical Bench

Very sturdy

[konakoa]

Updating this thread. I exposed several sheets of film with my lens to see if it needed shimming. I exposed numerous sheets with the rear element fully seated, then an equal number with it backed out one full turn on the threads.

Backing out the rear element required refocusing. Previously I could see a difference (in tiny details seen in my loupe) fully screwed in versus backed out on the ground glass. The image looked sharper on the ground glass in my 12x loupe when the rear element was backed out. I did multiple back and forth evaluations. The real test however is on film.

Long story short, making careful exposures (keeping everything fully labeled and tracked in my darkroom from camera to finished in plastic pages) there’s no difference in my lens if it’s screwed in fully or backed out. I looked at the negatives directly with the same 12x loupe. Again, I am looking at tiny, tiny details on the film. Nothing that would ever show up in the contact prints that will ultimately be made with this lens on the 8x20 camera.

Just for comparison I placed a Nikkor-W 210 in the sequence (no, not for covering 8x20 but just for the same focal length and magnification) and it and the 210XL were equally sharp on the same scenes with the same resolving power.

So my 210XL lens is fine as far as I can determine! Maybe my problem earlier is aging eyesight. Getting older is not fun.