On Tue, 9 Apr 2002, Paris, Leonard wrote: > Yes. That indeed was what I was trying to say. When you get a zoom > lens that doesn't maintain a constant aperture from extreme to > extreme, it's because they wanted to produce a cheaper, consumer zoom > and, in order to do that, the glass and barrel were made smaller, > making it necessary to limit the expansion of the aperture iris > diaphragm at the tele end. There fore, there was room for constant > aperture (f-number) only up to a limit. In other words, f/8 at the > wide end had plenty of room to expand to maintain f/8 at the tele end > but f/3.5 at the wide end ran out of expansion room at the tele end > and would only be (ratio-wise) f/4.8 or whatever.
Interesting... I've never heard of a consumer zoom with variable f-stops that stayed at the same f-stop at maximum aperture as you zoomed in, but which changed f-stops at smaller apertures... is this what you're saying is possible? > Len (Who was noticed by the boss as spending too much time on > non-company business) ---- Don't you ever think constructively about work on your own time? If so, then it all evens out in the end... :) chris - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
