Archived posting to the Leica Users Group, 2000/06/05
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]At 12:40 AM +0100 6/5/00, Christer Almqvist wrote: >Looking at some 16x b+w enlargements from shots I made recently in the >middle of the night in Dublin's Temple Bar district with my 35 mm Summicron >asph fully open using HP5 pushed to 800 in Rodinal 1+25 for 10 mins........ > >..... I get the impression that the depth of field with the asph lens is >much wider (or larger or deeper or whatever) than with the comparable >pre-asph lens. I try to explain this to myself in the following way: if >d.o.f. is defined as the area which the lens can render on film meeting >certain resolution criteria, then a lens with a higher resolution than >another lens (at the same fstop) will automatically have a wider d.o.f. > >Is this the correct explanation, or is there another one, or am I just >trying to find a justification for the lens upgrade? > >BTW, the Summicron asph is remarkable, sharp as it is fully open. The bokeh >is sweet as honey. I do not miss having an extra stop, I'll use the $ 1000 >I saved getting a Summicron rather than a Summilux to upgrade one of my >other lenses to asph as soon as I can find a demonstrator will full >warranty. > >-- >Christer Almqvist >D-20255 Hamburg, Germany and/or >F-50590 Regnéville-sur-Mer, France There is a certain truth to this, as the additional spherical aberration that the pre-ASPH Summicron has makes particularly the out-of-focus areas appear softer, broader (and smoother) than the ASPH will render them. The Summicron ASPH still has smooth out-of-focus areas, but in a more 'controlled' and tighter manner and not in quite the 'dreamy smooth' way that the previous lens had. * Henning J. Wulff /|\ Wulff Photography & Design /###\ mailto:henningw@archiphoto.com |[ ]| http://www.archiphoto.com