Le 8.9.2002 9:10, « I™zzet » <izzet@vizo.com> a écrit : > Then does it follow from here that > 1-The ONLY reason we loose resolution when we blow up an image on the > film is because of the grain and other impurities of the film itself, > and > 2-The resolution power of the optical system (lens) is infinite. No, 1) isn't the only reason.. 2) accounts for it too; the limit is the size of the circle of confusion we are ready to accept and this doesn't only depends upon the grain. Just think about it : some lenses are better than else and thus allows greater magnification, all lenses aren't equal and increasing magnification will makes their defects more apparent. If the perspective and spatial relationship stay the same, the image quality degrades itself a lot due to the magnification : why would we need to buy all these expansive lenses and drag them around if a single one could do it all ? Even digital SLRs bodies need several lenses although there is no grain in digital pictures..
