Archived posting to the Leica Users Group, 1998/02/07
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Dan Post wrote: > > Maybe I am just too easy going, or maybe I need my Prozac dose adjusted! The > miniscule spots in lenses are often unavoidable. I have seen the fine flakes > of black barrel coating in many lenses, and I have found that they rarely > affect the image. Are these flaws inherent in the process, and do they have > an effect? maybe Leica Q.A. knows something we don't consider- that these > 'flaws' have no effect on the photo. I have seen a couple of bubbles in the > wide eye of my Elmarit 135, but never gave it a thought. Would these count > as cosmetic flaws? > What gets me, working in a camera store, is the huge number of people who > come in wondering why they have a hazy flair on their prints, and when they > present their cameras, they have a crusty deposit of dust, fingerprints, and > lord only knows what else on the lenses! These folks have a serious problem! > Seriously, though, has anyone done any testing to see at what point 'spots' > would affect a lens' resolution and sharpness? By spots, I means something > like .2mm opaque spots (ink?) on the lens. How many needed to degrade a > lens. I know that random bubbles have no effect, but if there were enough, > it surely would degrade the image. Points to ponder. > Thanks, > Dan'l Dan, I agree wholeheartedly with your last post. I was a bit afraid to say these things previously for fear of it being considered blasphemy by some of the more radical elements of the group. ; ) Nikon customers can be just as obsessive. We once had a customer looking for a brand new 80-200 2.8 without any dust in it. After examining at least 6 lenses he finally settled on one that looked a little better than the others. He drove us nuts but eventually spent a lot of money. One demonstration that will make one worry less about specks is to take a dime and lay it on the front of a lens (a 50 1.4 works pretty well) and with the SLR pointed upwards, looking through the viewfinder, the dime is pretty much invisible. I'm sure a dime would degrade the image a bit, but not as much as most people think. (On an M camera I usually put a silver dollar on the lens, that really impresses them. ; ) ) Have a good day, Colin