Archived posting to the Leica Users Group, 1996/07/26
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]I have used two early 90-tele's and have had no problems at all; no fog, no internal mist, etc. I still have one that is at least 10 - 15 years old and it's perfectly clear. I do, however have a 90/2.8 Elmarit-R that does show internal fogging. I've been waiting for a slow day before I sit down to clean it. I've been under the impression for a number of years that the main problem with internal fogging of lens surfaces is a result of the slow (very slowwwww...) de-volatization of the lubricant used on the diaphragm leaves, at the pivot points, plus possibly the focus lubricant. But, the focus gear is usually pretty well isolated from the internal lenses by all the metal baffles that make up the various tubes and element holders. Having a few 1930's Leitz lenses, I have seen more of this fogging on newer stuff than old. Especially from the 60's and 70's. Al