Archived posting to the Leica Users Group, 1997/08/30
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]All, Following up on a previous (old) posting, suggest you do the following, which I did the other day: 1. Assemble all your lenses in a dark room, the darker the better. 2. Find a good flashlight, the brighter the better. 3. Set each lens to their largest aperture, shine the flashlight up into the lenses as you watch off-center from the other end. 4. Prepare to be startled. Now, I know many of you have been doing this for years, in search of fog and fungus in 40 year old glass, but I (in 25 picture-taking years) had never attempted it before, so was in for a shock. The dust resident inside all of my lenses (Nikon and Leica) ranged from minimal to frightening. Even my new 100 APO was filled with flecks of dust, and it's brand new, with ROM chip. My mint, used 180 2.0 has a center element with light circular haze/fog/cleaning marks off to one side. My 20-35 Nikkor zoom has a mildly fogged center element. My question are these: 1. Jeeez!! Is this normal?! 2. How clean, really, is clean? Should I see ANYTHING but glass reflections, or does everything I own have to go to Sherry for disassembly? 3. To what degree does what's on the lens elements significantly affect their optical performance? Sober (for now) in Maryland, I remain, sincerely, David W. Almy