Alan Bell schrieb: > > I occasionally see ads for lenses that say "small scratch on the front > element but doesn't affect picture quality." Can someone discuss that > proposition. It must affect picture quality to a degree, otherwise > manufacturers sell them pre-scratched. :-) What is the effect of a > scratch? If I'm really picky what will I see? >
Hmm, there are scratches and there are SCRATCHES ;-) I have a really small scratch on the front element of my 80-200/2.8L and I never saw anything of it in my pictures. Now, this is a REAL small scratch, barely visible only if you find the right angle to look at it against a light source. If you had to check the lens inside a store, you would probably not see it. If it were a big scratch, it might show up as increased flare, reduced contrast. If it were REAL big and have a size of one or more percent of the front element, it could be a real problem and show directly on film, the corresponding part of the picture being unsharp and maybe even as an unsharp bright picture of the scratch itself. A lot depends also on the focal length and the shooting aperture. Smaller focal length and smaller aperture (bigger number) will make it worse. Thomas Bantel * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
