Matthew Newton , Apr 13, 2012; 11:21 a.m.
Interesting information. One thing to keep in mind however, there are two optically different versions of the 85/2. The original single coated version, serial numbers up through 115,000 use a 6 element in 4 group design. The later multicoated versions (serial numbers over 115,000) used a 5 element in 4 group design. Instead of the 2nd group (starting from the front of the lens) being a cemented doublet, it was changed to a single element, same exterior shape/dimensions. Also the handful of lenses tests that actually compare the first to second optical versions of the lens, plus a lot of anecdotal evidence says that the change resulted in the 5/4 e/g later version to be significantly sharper than the first version of the lens.
I have the later version (actually the final version, which are serial numbers over 200,000 which have a newer multicoating that Olympus Zuiko was using in the last versions of their OM lenses before production ceased). In my experience mind is quite sharp even wide open at f/2. It is actually probably my sharpest OM lens wide open and just gets better stopping down. The only lens I have that might be better for center sharpness is my zuiko 24/2.8, but the 85/2 deffinitely exceeds it in corner sharpness wide open (and that is f/2 compared to f/2.8). It does have beautiful Bokeh.