I have a second version 28/2.8M(http://www.bdimitrov.de/kmp/lenses/primes/wide-angle/M28f2.8-ii.html ) that is much sharper at 4 than at 8. I checked is several times to be sure I didn't mix up the slides. Maybe these are really 1.4 lenses dumbed down to 2.8 at the aperture? Bill Lawlor
