Interesting opinions in here. Seems to me lens selection is not usually an all-or-nothing proposition. While one lens may be prised for its resolution & low distortion, it may produce less than optimal results for depth of field, speed, or color rendition, etc. I'll gladly live with a little barrel distortion if it comes with great color. I'll also give up a few stops of speed if the faster lens has so little DOF that I can't snap a good low light portrait. It matters.
I find the really fast lenses tend to have a too narrow depth of field for my liking, so I migrate toward the mid-speed and slow end of the scale. I also looked at the gallery of pictures from the pbase.com shootout and found the f1.2 photos a bit cool and the color subdued compared to what I'd expect from the subjects. The photos were plenty sharp, but that's only part of the formula for a good lens. The Takumar 1.4 pictures were warmer & had a more pleasing bokeh, IMHO.
That shootout is a good source of comparison photos if you're in the market. My preference (as you might guess) is for the A series 1.7, and I like the A series 2.0 equally as much.
Here's more data on lens comparisons for the pentax 50s from
jcolwell.ca - home :
- OK, but not particularly notable performance
* good
** very good
(!) excellent
(!!) great, exceptional, best of the (!)
x poor, and/or low resolution (relative to similar f, Av)