On Thu, 20 May 2004 17:23:24 -0600, you wrote: > >----- Original Message ----- >From: <[EMAIL PROTECTED]> > >Subject: Re: A 15mm-85F2 (was RE: 77 limited or 85* for >portraits/canndids) > > >> Portrait >> lenses don't have to be sharp!!! > >This is not to imply that the M85mm is soft, I hope. >What I don't understand is the insistence of extremes that this list >is so fond of. >The M85 may not be as sharp as the K585, for example, but this >doesn't mean it isn't a good sharp lens, it just means that the K is >sharper. >Apparently, the M 28mm suffers from the same crisis of quality. >Perhaps there are better lenses out there, but it's not like as if >the M is crap. > >William Robb
The*istD and idle hands make for some easy comparisons. Please flame away all you like about how bad this is for a lens test, it pleases me, so that heck wit ya, na na na na naaa. I chose a subject distance suitable for the lens in question, i.e. 3.3 meters for the 85mm, which gives a full head-and-shoulders shot. I used Rob's excel spreadsheet to calculate lpmm for three lenses at available apertures f2-f8: the M85/2, FA 100/2.8 Macro, and a manual focus Vivitar VS1 28-105/2.8-4 (fairly new cheap lens, not some old cult classic). Shots were manually focused. I used the *istD mounted on a nice stable Ries wooden tripod, 2-sec mirror prefire, actuated by the cable release I modified from PZ to istD using PDML instructions (thanks guys). Numbers such as 0,3 show the group and pair resolved. The test target is one I keep pasted on the rec room wall for just such misadventures as this. The short story - from f2 through f4, the M 85 at 3.3 meter subject distance is the clear winner, and maintains a slight edge at f5.6 and f5. This was surprising to me, but heck I saw it with my own eyes. The 100/2.8 Macro resolves one small increment more at f8, being Group 0, Pair 6, but the spreadsheet penalizes it a bit for 100mm length vs 85mm, so the lpmm value is smaller. M85/2 2 0,3 48.9 2.8 0,3 48.9 3.5 0,3 48.9 4 0,4 54.9 5.6 0,4 54.9 8 0,5 61.6 FA 100/2.8 Macro 2 2.8 0,4 46.7 3.5 4 0,4 46.7 5.6 0,5 52.4 8 0,6 58.8 Vivitar Series 1 28-105/f2.8-4 at 105mm 2 2.8 3.5 4 0,4 46.7 5.6 0,5 52.4 8 0,5 52.4 -- John Mustarde www.photolin.com
