360mm f6.8 Symmar-S MC Copal

[neil poulsen]

It's possible to have the cell spacing on either tweaked if performance at infinity is the primary concern, but most users never feel a need for that.

This is interesting. Who can do this.

Is it the spacing between the front and rear groups, or is it a spacing within a group?

I've heard the some of the Red Dots came with spacers that altered the lens between it's being optimized for infinity or for closer distances.

[Oren Grad]

Oren,

I will begin a search for a well maintained Apo-Ronar.

It's possible to have the cell spacing on either tweaked if performance at infinity is the primary concern

.

Not sure what this means.

Briefly, the exact spacing between the front cell (the glass in front of the shutter) and the rear cell (the glass behind the shutter) affects whether the optical correction of the lens is optimized for close work or distant work. The spacing can be changed by installing a shim between one of the cells, typically the front cell, and the shutter, or by removing a shim that was installed at the factory. However, it's not something you'd do yourself - the manufacturer (Schneider or Rodenstock) would have the tools needed to make sure the thickness of the shim was correct for the particular sample of the lens.

See, for example, this thread...

http://www.largeformatphotography.in...ad.php?t=14422

...and this one:

http://www.largeformatphotography.in...ead.php?t=9113

I don't think this is something you need to worry about now, just a fact to stuff in the back of your head for future reference. Once you've gained more experience, you'll know enough to judge for yourself whether it matters for your work, and you can take action, or not, accordingly.

[Peter K]

This is interesting. Who can do this.

Is it the spacing between the front and rear groups, or is it a spacing within a group?

I've heard the some of the Red Dots came with spacers that altered the lens between it's being optimized for infinity or for closer distances.

It is the spacing between the front group and the shutter or barrel.

To adjust a lens like an Apo-Ronar or G-Claron for infinity work one can follow the procedure described in "Internationale Phototechnik" 8/1993.

Focus the center of your ground-glass on fine structures in the distance like leafless trees or high grasses with a strong loupe at wide open aperture.

Shift the rear frame of your camera to the left and the front frame to the right up to the point you can see the structures get blurry.

Unscrew the front group of the lens circa 2 mm (1 line or 0.08 inch) from the shutter or barrel and look for the fine structures, twigs or leafs. Adjust the distance between the front group and the shutter up to the point the structures are as sharp as possible without any coma and blur. Refocus if necessary during the adjustment.

Place a steel or brass shim of the determined thickness between shutter and front group. If the thickness of the shim is the correct one there is no difference in image quality between the center and the edge of distant subjects. For close-up work remove the shim or place a much thinner one.

Peter K

[Mark Sloane]

Guys,

You haven't mentioned the Tele-Xenar 5.5/360mm in your recommendations. Any reason why? It appears to be small enough for backpacking, will cover 5x7 (?) and has a 67mm filter size.

[Mark Sloane]

I think I got my answer to the Tele-Xenar question. Although the lens is a 1990s vintage, it is a telephoto lens and not a process lens and therefore not as sharp. Do I have that right?

I don't expect to make large prints...I like 8x10 and smaller and expect to make contact prints with the 5x7 back.

If I did want to make 16x20 prints, would I notice a difference in sharpness/resolution between a telephoto lens and a process lens?

[David Vickery]

I think I got my answer to the Tele-Xenar question. Although the lens is a 1990s vintage, it is a telephoto lens and not a process lens and therefore not as sharp. Do I have that right?

I don't expect to make large prints...I like 8x10 and smaller and expect to make contact prints with the 5x7 back.

If I did want to make 16x20 prints, would I notice a difference in sharpness/resolution between a telephoto lens and a process lens?

Yes. Most likely or at least probably. I would not buy the tele lens. My opinion only, but forget the tele! I have one that I used a few times and it has been in a cabinet for years. It is not as sharp or versatile or as easy to use as the other, regular lenses.

I Happily use a 355 G-Claron on 8x10 and 11x14. It is great! The Symmar is also a great lens but not the best choice for what you want to do at this time, as others have said - large and heavy. I bought my 355 in an enlarger barrel and I took it out of that and put it in a copal-3 shutter.

The Ronar would be an excellent choice as well, due to its superb sharpness and small size.

Some other excellent choices (except for the filter problem) would include the 14" Commercial (or Eastman) Ektar, 14" Dagor (barrel lenses are much more affordable than the ones in shutters), the Artar (red dot or not), and there is probably a fuji lens in that focal length.