90/2.8 Tele-Elmarit-M (thin version) variants

<p>My question has to do with the glass fungus or white spot etching to the sealed rear elements and it's prevalence in the early and late versions. My research has shown the lens had two versions. The first had a longer focus throw as easily identified by the inclusion of a 50 ft. engraving on the distance scale. These were produced in the 70's and about 5-10% of the early samples went on to develop the "TE glass disease" as some would call it, presumably due to a reaction of the lubricant to the glass. The second version appeared in the 80's and had a redesign of the focus ring to a shorter throw as demonstrated by the more compressed distance and dof scale compared to the earlier version. The easiest way to identify it though is by the engraved yellow-orange 90 on the side of the barrel base and the small 'tic' marks on the dof scale. I would like to think with this redesign of the focus mount the lubricant had also changed, thus eliminating the problem but I'm not entirely certain. I recently saw a 90 TE on eBay of the later version with a couple of white spots on the rear glass that were permanently etched into the glass. Anyone know the latest scoop on this problem?</p>

<p>Mine was the Leica reps sample in 1986 and does not have the problem. I also got his viso 111 and black 65 Elmar all at the same time.</p>

<p>I know from my sample that the lenses seem really prone to cleaning marks--maybe something with the coating?</p>

<p>Had two samples of this lens with serial numbers in the early 3 million. Never experienced any glass problems, only an eventual slightly loose heilcal focussing after considerable use (15 years). Liked the longer distance resolution and "tone" of the lens in B&W work. Maybe the spots are due to humid and warm atmospheres?</p>

<p>Hmm - my 90 TE-M has:</p>

<p>a serial number starting 29.., yellow "90" engraved on the barrel, "50" feet engraved on the focus ring, 180-degrees+ focus throw, DOF markers with straight diagonal lines - and no glass disease.</p>

<p>Seems like the "variants" aren't clear-cut?</p>

<p>Mine is from the 80's - a S/N 32... which came with the screw-on rubber lens shade. A bit different than Andy's</p>

<p>(following his format):<br /> yellow "90" engraved on the barrel, "25" feet engraved on the focus ring, 90-degrees+ focus throw, DOF markers with straight diagonal lines - and no glass disease.</p>

<p>I didn't know there was so much variation in one lens type - even the distance scale. Interesting.</p>

<p>I owned the earlier version for about 7 years and thankfully never experienced the problem, which seemed to be an urban legend red flag, but I never saw it on friends' lenses either. It was a thoroughly enjoyable lens to use. Its only drawback for me was that the lenshead wasn't usable in a Visoflex.</p>

<p>Further research on the net indicates that lenses with a sr.# above 3,20x,xxx are pretty safe from the 'TE disease' so it appears even some of those with the short focus throw are not entirely safe. Practically speaking, since only about 5- 10% of those under the 3.2 mil. sr. # are prone to the problem, so if they haven't developed it by now, the risk is reported to be very low at this point. One explanation I've read deviates from the lubricant theory. It states that the coating used were porous to moisture in the air and when it seeps under the coating there is a reaction with the heavy metal in the glass forming a corrosive material. This corrosive material eats away at the pores leaving silver/gold flecks on the glass. Maybe the later versions used a different type of glass or coating process, something Leica tended to do silently during the life of some of their lenses. </p>

<p>I have had two versions: one with earlier serial# which was made in Canada, never had any issue with it and a very good,compact performer; the other one with very late serial # and was made in Germany, performs as good as the Canadian one and didn't notice much difference.</p>

<p>I didn't know there were so many variations either. Mine is serial nr. 3378xxx, 25ft on the distance scale, has the little tics on the DOF scale, and clear glass. A cracking little lens too.</p><div></div>