Are Symmar and Ektar lens cells matched?

[Simon Benton]

I have a 135mm Symmar and an 81/2 inch Ektar with just the front lens cells. Were the rear lens cells matched or would any rear lens cell from a similar lens be OK? Any info. greatly appreciated.

[Ole Tjugen]

Since the Symmars were made as convertibles, the rear cell alone must be reasonably well corrected. That again means that using a different cell should pose no problems.

[Don Dudenbostel]

I recently had a 121mm super angulon repaired by Schneider USA (California). I had dropped the lens and broken two internal elements in the rear grouping. I picked up another 121 from KEH where the front had been damaged and the back was perfect. I put the two good halved together to find they would not work properly. To make the story short it was a bent shutter that was the problem but in conversation with Schneider the tech said I found a very good match for the front set. He explained that Schneider matched the front and rear cells and that all cells are not perfectly matched. He said this is true of all of their lenses. Another Schneider rep told me that this is the case as well. It may work but not to an optimum level compared to a matched set. I found it interesting that the tech and rep both told me that when Schneider bought the Goerz company they did not hire the techs that made the RD Artars. There were apparently three tech that knew how to produce these lenses they way they should be done and in a quantity large enough to make money. According to the Schneider folks the Schneider company could not reproduce the lenses with the same precision that the Goerz tech did. He explained that each element had to be matched to each other element to achieve the quality of the RD Artar and that it was totally a hand process.

[Sevo]

According to the Schneider folks the Schneider company could not reproduce the lenses with the same precision that the Goerz tech did. He explained that each element had to be matched to each other element to achieve the quality of the RD Artar and that it was totally a hand process.

I'd put that into the realm of legends and folklore - it is perfectly feasible to match a lens way beyond large format specs with current measuring equipment and tools, and even more trivial if you own all information on the internals. It will have been the economics of moving a previously manual process to robot production, when the former sold so sparingly that it only employed a staff of three - it might have taken a decade or more to recoup the investments, and anything like that is taboo in a shareholder value centric world.

[Ole Tjugen]

Wide angle lenses like Super Angulons are a very different matter, where a tiny difference in spacing will throw it off completely.

Convertible and more-or-less symmetrical lenses with "normal" angle of view are relatively safe to "mismatch", wide-angle lenses (like Super Angulon) and highly unsymmetrical ones (like Tessars) are not.

[IanG]

Wide angle lenses like Super Angulons are a very different matter, where a tiny difference in spacing will throw it off completely.


Dean (razzledog) started an interesting thread on APUG about 90mm Angulons and cell spacing, he modified his and achieved much better sharpness. The 90mm Angulon is notorious for quality differences between individual lenses.

Ian

[Gene McCluney]

Just to clear up a small point. You absolutely cannot put an Ektar rear group and a Symmar front group together and get a working lens. They are different designs entirely. The Ektar is not a convertable lens design.

[Don Dudenbostel]

To continue with the information Schneider told me this past summer.

The tech also told me that the current lenses like the XL super angulons and symmars are so precisely ground that elements are completely interchangeable without problems. The older lenses required matching elements (per the Schneider techs info) to a particular grouping if one or more elements were to be replaced. Grinding wasn't that precise prior to the XL series or at least like it is today. In the XL series the elements are ground by blasting the glass with a magnetic abrasive slurry using magnetic fields of varying intensity to direct the abrasive. He said this is how aspheric elements as well as spherical elements are done now and how such high precision grinding is achieved. He stated that Schneider has large collection elements and mechanical parts in storage in Germany to repair or rebuild almost every model lens they have made over the years. Apparently they hold back a small quantity of all of their parts and hold them in an archive for repairs but in the case of older lenses they may not be a perfect match with what you are having repaired.

I don't think swapping cells from the new XL's would be a problem but the older ones I don't know if it would result in optimum performance.

(I'm only repeating what Schneider people have told me.)