I understamd = but if all things are equal, then you would have f2.8 the same optical quality in both designs, but would also have a f1.2 , event hough it will not be very good optical, but at least you will have it. Maybe I am missing something - sorry if these questions are stupid, but it seems to me that we are limiting the performance of the lense to get good consistent quality over the range. But can't we get that and also have not so good <f2.8 available as well? -e > --- "Icoz, Evrim" <[EMAIL PROTECTED]> wrote: > > What's the advantage of having a constant aperture > > zoom then? Aren't we > > losing useful aperture at the shorter end if we are > > limiting ourselves to > > the center? > > Not really. The optics of the lens are such that to > have (for example) a 70mm f1.2 at the wide end of the > 70-200/2.8 would either perform poorly and/or vignette > badly, unless very large diameter and very costly > glass were used. * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
