Apo-Ronar shims--one, two, or none?

[CreationBear]

I'm trying to get a feel for lenses available in the 360mm range and am finding that the Apo-Ronar and Apo-Artar's are ticking a lot of boxes. Complicating matters for me, though, is understanding the whole shim business--I get that shims are used for optimizing performance at distance, but assuming I'm looking at an Apo-Ronar in a modern, black Copal 3:

1.) Is there any way to tell I'm looking at a factory-installed shutter, or whether someone has done the job with "aftermarket" parts?

2.) How many shims should a 360mm have? I've seen sellers' descriptions of Apo-Ronars in Copal 3's as having one, two, or in the case of shorter lenses, no shims at all. Should a single shim ring be a danger sign?

3.) As of yet, all of the conversations I've seen about shims have been about Rodenstock lenses--do Apo-Artar's use them as well? Also, I've noticed the in-shutter Schneider's seem to sell for a bit more than do the Apo-Ronar's, which was surprising to me given the latter can have more modern lens coatings. Are there simply fewer Apo-Artar's out there, or is there a "pixie dust" reputation to consider?

Any insights appreciated!

[Leigh]

All manufactured part dimensions have tolerances. That includes lens thickness and surface curvature, spacer lengths, etc.

Shims are used to optimize the spacing of the cells to compensate for these tolerances to the greatest extent possible.

So the number of shims required will vary from one individual lens to another.
Determining the required shim(s) if any requires an optical test bench or fixture.

- Leigh

[Bernice Loui]

Shims are specific to one individual lens cell set in the case of Rodenstock. Rodenstock calibrated each shim for each lens cell set and and shim position. They are NOT interchangeable, not universal and not to be discarded as these shims will affect optical performance of that specific lens. It is also possible for a used lens these shims have been removed, discarded or lost since a given APO Ronar has been purchased new. There are some APO Ronars that have no shims, many do.

Goerz APO Artar, Red Dot Artar, Dagor and .... have lens barrels that have been individually adjusted (length overall and distance between iris to lens cell) to the specific lens cell set. This method is more involved and requires each individual lens to be tested then the lens barrel or lens cell mounting rings precision machined to match the optical requirements of the specific lens cell set.

Goerz lens cells are not interchangeable between Goerz lens barrels without very specific modifications. Rodenstock APO Ronar lens cells can be interchanged IF the lens cell set specific shim accompanies the revised mounting.

360mm APO Ronar comes in a #3 shutter, Goerz 14" APO Artar_Red Dot Artar was originally supplied often in a Ilex#4 shutter. Optical performance wise, they are both remarkably similar multicoated or single coated depending on optical condition of a specific lens. Some are excellent, some have been whacked over their course of their history resulting in less than original optical performance.


Bernice

[Tin Can]

Another question is how do we make and use a DIY Optical Bench.

[Luis-F-S]

If it’s a black Copal 3 it’s probably newer than the lens so not original. Only way to tell if the spacing is correct is on an optical bench. If it was installed correctly they would have transferred the spacing from the barrel.

[Bernice Loui]

After Goerz was purchased by Schneider, Schneider offered the same Goerz APO Artar in Copal, Compur, Prontor shutters, Sinar offered both APO Ronar and Schneider APO Artar in DB & DBM mounts they were "multi coated".

The modern Copal shutter has a non-round iris, the older Ilex and similar shutters have a nice round iris. If the Ilex or older shutter is in good condition, there is no functional advantage to the Copal shutter, chrome or black. IMO, the chrome shutter speed ring Copals are made a bit nicer as the black ones appear to be cost-reduction_ed.

Lesser known detail, f9 Goerz APO Artars (Red Dot or Schneider Artar) are optimized at f16. Rodenstock f9 APO Ronar are optimized at f22. Theoretically the Goerz has better optical performance at f16 than the Rodenstock.


Bernice

[CreationBear]

Henry Ford wept...

Thanks so much for the replies--very much appreciated!

[Pere Casals]

Lesser known detail, f9 Goerz APO Artars (Red Dot or Schneider Artar) are optimized at f16. Rodenstock f9 APO Ronar are optimized at f22.

Bernice, you may check Arne Croell and C. Pérez tests. The Ronars perform exceptionally well at f/16, and in both cases (Pérez-Croell) the ronars show better performance at f/16 than at f/22.

For example Pérez metered for a 1970s APO Ronar 240mm:

f/11 76 68 38
f/16 68 48 54
f/22 60 42 48

76Lp/mm at f/11 in the center is a nice rate for a 1970s glass !

For that sample, if DOF not counting and not having important stuff in the corners then best aperture is f/11. Also perfect corners at f/16, and we may stop further if wanting DOF.

As always this was a practical test at contrast extintion, not a lab test, but to say 76 or 54 he had to see a certain group.element !

Probably the optimal aperture depends on the particular sample, but from the numbers it looks that nobody would guess the aperture from the image quality, beyond DOF...

[Mark Sampson]

Well, we're talking Rolls-Royces here, not Model Ts. Not to disparage Mr. Ford's fine cars, but these lenses were limited-production items, hand-made to extremely tight specifications... and very expensive when new. The professionals who bought them new were happy to pay to get the best quality (on which their livelihood depended).
If you want the best performance from your lens (don't we all?) the methods outlined above are what it takes. There ain't no free lunch!

[Bernice Loui]

Absurd (Those ??? LPM numbers again) to apply test from a single lens sample to the entire production of any lens. That individual lens test is a specific isolated test example.

This entire family of Dialyte lens formulations can be exception in optical performance, their trade off is smaller (about 45 degrees) image circle than other optical formulations that offer much larger image circles of good optical performance. Beyond Rodenstock APO Ronar and Goerz APO Artar, there is APO Nikkor, 203mm f7.7 Kodak Ektar, Zeiss Jena APO Germinar and a host of other Dialyte lens formulations that were produce for the process camera and color separation printing industry back in the day. Any of these that are any good have been individually hand tweaked to achieve ideal performance for a given set of lens performance demands and specifications. These needs are often FAR more demanding than any normal photographic needs.

Majority of these Dialyte lens formulations are in barrel as they were most common on process cameras. They are a lot less expensive in barrel to due the lack of a shutter which is easily resolved with a Sinar shutter or similar.

Been using this family of lenses since the 1980's with excellent results for any image needs with a taking aperture of f16 to f45 and longer than normal focal lengths.


Bernice