The Pentax-A 55mm f/2.8 is a manual focus lens made to old-style standards: metal. Build quality and focus “throw” are much better than the new Pentax-D FA 645 55mm F2.8 AL[IF] SDM AW. But optical performance is little better, if at all.
As will be seen performance is reasonably good, but with moderately strong lateral chromatic aberration (red/cyan color fringing).
This is the entire frame as shot (shade).
I used a Zeiss 3X focusing loupe on the viewfinder to focus as well as could be. I shot two series. Both were sharp, so I think this represents what the Pentax-A 55mm f/2.8 can do.
Article continues for subscribers...
If you’re already a subscriber, CLICK HERE TO LOG IN
diglloyd Advanced Photography includes hundreds of pages of exclusive coverage and high resolution, Retina-grade example pictures detailing Canon and Nikon DSLR bodies and their lenses, with in-depth analysis of sharpness and contrast, color, bokeh, vignetting, distortion, MTF, and flare. Also included is a wealth of in-context technique and workflow insight. Since 2006, diglloyd Advanced Photography is the authoritative review and on-line reference for discerning Canon and Nikon shooters. Subscriptions cost $ per year.