> If I use teleconverter, let's say 1.4x, does it "improve" me > picture quality in some way? Forget for now about sharpness loss, > but as long as TC takes an image that comes from the center of the > lens, than magnifies it and cuts off image that comes from corners > (it seems to work similar way as a closing down diaphragme by one > stop) so would it improve in some way the picture? Shouldn't whole > picture look equally good in center and corners in this case?
Nice wish, Waldemar, but I don't think so: 1. A TC really is not doing exactly the same thing as "closing down diaphragme by one stop" (etc.). I guess it does blow up the center area of the image, as you have described. 2. A TC will add its own softening-toward-the-corners, so that, even if you did really have a "TC-cropped" image that was truly even in quality corner-to-corner to start with (which, by itself, is probably an unlikely assumption), the TC would end up softening the edges more than the center, so you'd just end up with just another soft-in-the-corners image. The above is not to say that I don't like TC's, or don't use TC's sometimes (because I do, and I do), but to say that I think your wish will go unfulfilled - <g>. Just my 2 f-stops worth... Fred
