Archived posting to the Leica Users Group, 1996/07/22
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]
I had an interesting conversation with Don Chatterton this morning. I
inquired about a used, late model, 90mm Tele-Elmarit for my M6. With a
concerned tone in his voice he said he might have some but that he wasn't
sure what condition they were in. As he rooted around in his collection,
he explained that the lubrication used in the lenses was sperm whale oil.
The sperm whale oil evaporates when it's warm and forms an occluding film
on the interior lens surfaces over time. Since the rear element is glued
in place on the Tele-Elmarit the interior surface cannot not be accessed
for cleaning (at least not without destroying the lens).
He said that he is able to sell only one (1) in four (4) or five (5) of
the lenses he gets. The rest he discards due to this damage.
He had a lens that did not show the evaporation damage. I asked if the
lens would be useable five years down the road, and he was not
encouraging.
According to him, the oil vaporization problem is not limited to the
Tele-Elmarit, but other older lenses have elements that can be cleaned.
In conclusion he recommended a new or recent (used) lens since Leica has
switched to synthetic lubricants that do not vaporize nearly as easily.
He also felt that the optical quality of the new 90mm lenses was clearly
superior to the Tele-Elmarit and the size difference was not great.
I am now considering a new 90/2.8 for this reason.
I'm returning to the list after a two month absence, so if these issues
have been covered recently I apologize for the redundance.
-Charlie
-------------------------------------------
Charles E. Dunlap
Earth Sciences Dept.
University of Calif.
Santa Cruz, CA 95064
cdunlap@earthsci.ucsc.edu
408-459-5228 (office) 408-459-3074 (FAX)
-------------------------------------------