Scratches are difficult to assess. I have an M40/2.8 that came with strange damage. On close inspection, part of the lens coating has been eaten by fungus. The edges of the lens are microscopically crazed. Wide open you can see this. After f4 or f5.6, the damage is hidden.
In comparison to other copies of the M40/2.8, it was difficult to find the damage to the final pictures. I finally succeeded in the Kansas City airport with a dark waiting room shot including a bright window in the background. Here it showed some extra flare. Overall, minor damage is very difficult to see in the final results. Regards, Bob S. On 2/15/06, Jens Bladt <[EMAIL PROTECTED]> wrote: > Scratches will probably reduce the overall contrast of the images. So, The > scratch will affect image quality, even if it is not visible or > recognizable. > > The only way to actually see it, is of course to compare to photographs made > by the same lens model, but without the scratches. This is rarely possible. > I do believe, however, that it is very difficult to measure or see any > differences as long as we are talking about a few minor scratches. Scratches > at the rear element will probably have a greater impact on image quality > than scratches on the front element. > > The greatest impact that scratches have is that of the sales value ;-) > Any seller will realize or experience this ;-) > > I recently bought a used lens with a 1x1 mm nick in the front element. This > lens was tested (by Jostein) against a similar lens of a competing brand > which was unscratched. No difference in image quality appeared to be visible > at all. > > But the effect on the sales value was quite significant. Lucky for me - as > long as I'm not selling it. > At auctions, however, the bidders will determine the sales price ;-) > > Regards > Jens > > > Jens Bladt > http://www.jensbladt.dk > > -----Oprindelig meddelelse----- > Fra: Igor Roshchin [mailto:[EMAIL PROTECTED] > Sendt: 14. februar 2006 00:27 > Til: [email protected] > Emne: scratches on lenses > > > > Every so often I see a claim in a lens description: > "These scratches don't affect the quality of your photo." > > What does one think when writing this type of statement? > That you don't see the scratch on the photos? > Even if a half of the lens area is covered by scratches you might > not see the scratches on the photo.. > > Well, this is a somewhat rhetorical question: > "How do you know that the scratches don't affect the quality of your > photo?!" > Personally, I would say that all scratches that are within the > entire beam diameter used in imaging DO affect the quality of photos. > So, the meaningful interpretation of the original statement would be: > "I didn't have the way of knowing any better image quality". > > Would you agree? > > Igor > > > >
