Archived posting to the Leica Users Group, 1997/02/24
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]>To me, the limiting factor in image quality these days is the size of >the negative. I think the better 35mm optics are far superior to the >film we have available. If there is some superiority to Leitz lenses, >it's probably only measurable on an optical bench. If you can't >capture the image on film, because of the limitations of grain, what >difference does it make? This is definitely not true. The most recent films (and some older = ones (Technical Pan) are far superior to almost any lens in = production. That's the reason why Leica is now in its first major = optical upgrading since 1979. The new films dictate new optical = recomputations to take advantage of the image qualities on film. >On a related note, there is a lot of fuss made by some about how >wonderful some lens or another is at full aperture. While shooting at >full aperture may make for an interesting effect at times, and may >make it possible to get any image at all in some circumstances, most >of the time it results in an image in which most of the subject is >out of focus due to narrow depth of field. What good is all that >resolving power to anything in the image that doesn't happen to be >right on the plane of focus? Again not true. If a lens at full aperture is better than another = one, then the optical qualities will be better till let us say f/5,6 = or f/8,0. After that aperture the levelling off begins. If you focus correctly at full aperture there should be no = 'out-of-focus-problems'. Especially Leica makes sure that the optical = plane of focus is within very narrow tolerances (1/100mm) to the = mechanical one, i.e. the negative. The narrow field of depth you = mention is relative. When shooting at 3 meters with a 90mm at 2,0 or = 2,8 the depth of field is =B140cm and =B1 50cm, more than enough to = capture the "thickness" of a human being or a cat. A well correced lens will not only be exactly sharp at the plane of = focus, but also axcceptably sharp before and behind this plane. = Again, here is an area where Leica is still superior to other lens = makers. Erwin Puts