Archived posting to the Leica Users Group, 1997/08/30
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]David W. Almy wrote: > > 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 David, 1. Don't ever go in the darkroom with your lenses and a flashlight again. 2. I think Sherry's busy enough. 3. Have a beer for every speck of dust you think you saw. You'll be fine. Colin