Upload & Sell: On
Following Zuiko 50/1.8 vs Pentax M 50/1.7 http://www.fredmiranda.com/forum/topic/1189378/0#11342210 ...
...here's a comparison of three 50mm lenses, Olympus OM 50/1.8 MC (2366xxx), SMC Pentax-A 50/1.7 (1218xxx), and SMC Pentax-A 50/2 3474xxx).
I'll post a total of three sets of four images.
1. all lenses wide open
2. all lenses at f/2.8
3. all lenses at f/8
Each image is a four-panel screen capture of PS CS6 windows; three are 100% crops from each of the three lenses, and the fourth is the Navigator window, with a red square to show where the crops are located in the full images. The 100% image crop panels are arranged as follows.
top left: Olympus OM 50/1.8 MC
top right: SMC Pentax-A 50/1.7
bottom left: SMC Pentax-A 50/2
bottom right: Navigator window
Method: 5DII CR2 RAW files (no PP), ISO 100, tripod, MLU, 2 sec self-timer. Three images were taken at each aperture, for each lens, with focus/defocus between each image, using LiveView manual focus. The first step was to select the best image from each set of three, and then use that particular image for all 100% crop views. IOW, the 100% crops for a given aperture are all from the same image, not (for example) the best top-right image from one photo with the best bottom-left edge from another photo, and etc.
Summary: Oly wins this particular test at infinity focus.
Caution: I only tested copy one of each lens, variation between copies for a particular lens can be significant. OTOH, the results are very consistent.
Set 1, wide open.