On 26 Jul 2002 at 13:44, Jose R. Rodriguez wrote: > I have the K50mm f/1.2 instead of the A50mm f/1.2 (same optical formula). Even > though other Pentax 50mm lenses may be capable of higher resolution than my > K50mm f/1.2, I have become quite fond of the "look" the photos this lens > produces (nice bokeh, great color, and excellent resolution..). > > I feel they are much nicer than the photos I shot with my M50mm f/1.4.
This sort of comment comes up again and again, I don't wish to sound like a broken record but the differences between the resolution of the Pentax 50mm f1.2 and f1.2 lenses is pretty much academic. The absolute resolution difference is only tens of line pairs per mm when the lenses are critically focussed on a planar target. <big theoretical speculation> Herein lies the issue, the DOF is so much more shallow on the 1.2 lens that all visible objects outside the absolute plane of focus are more quickly rendered soft hence the apparent feeling that the lens is softer. Just to further the theory my perception of sharpness and DOF from my A50f2.8 Macro is far more critical than I would normally expect from a short f2,8 lens, I expect that it seems this way since the actual plane of focus is so sharp and that the focal plane is flatter than non-corrected lenses. This leads me to the other point concerning the f1.2 lenses, it appears that they aren't at all well spherically corrected ie the plane of focus is not so much a plane but covers a spherical field. The slower the lens the less this effect is apparent therefore the f1.4 and f1.7 lenses suffer less spherical distortion and provide a different rendering of the same scene regardless of absolute sharpness. </big theoretical speculation> Well as the owner of 4 Pentax 50f1.2 lenses that's my bigoted take on it, I'd be happy to be corrected :-) To see the visual effect of a very fast lens with no spherical correction see the following Noctilux (50f1) and Summilux 75 (f1.4) images produced by Rei a member of the LUG (Leica Users Group): http://www.shinozuka-family.com/200110autumnlux1/ and most specifically: http://www.shinozuka-family.com/200110autumnlux2/kittyleaves4.jpg http://www.shinozuka-family.com/200110autumnlux2/tedkitleaves2.jpg PS I do also own a Noctilux and various other Pentax 50mm lenses so I have engaged in comparisons. Cheers, Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications.html - 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 .
