Archived posting to the Leica Users Group, 1999/10/06
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]At 08:50 AM 10/6/99 -0700, Kotsinadelis, Peter (Peter) wrote: >With all due respect, no lens performs better wide open than stopped down. Well, Peter, with all due respect, I didn't say that. There are lenses that are at optimum performance wide open. The 280 f/4 Apo Telyt is one. It doesn't get worse on stopping down until you get to small apertures where all lenses degrade because of light passing on the edge of the aperture scatters light. On the other hand, those lenses don't improve with stopping down either. That's what optimum at the widest aperture means. Most Leica lenses do improve on stopping down - more like 1 or 2 stops, as opposed to 3 and 4 stops with some other brands. And differences may not be as big for most Leica lenses. Nikon and Canon have a few lenses like that too. It's not unique to Leica. It's not common, but those lenses do exist. There are some large format APO lenses too used for pre-press that are supposed to be optimum used wide open (like f/9) so it's not all that uncommon with any format. Given a certain minimum focusing distance is respected. And isn't the Hasselblad UV lens also optimum wide open? (Who would have much use for a lens with Quartz elements anyway?). Eric Welch St. Joseph, MO http://www.ponyexpress.net/~ewelch There are two kinds of photographers: those who compose pictures and those who take them. The former work in studios. For the latter, the studio is the world.... For them, the ordinary doesn't exist: every thing in life is a source of nourishment. -Ernst Haas