John,
After seeing your post of the Minolta M 40f2, I tried to locate all my CLE stuffs (I think I have two sets) and found only one body, 28f2.8 & 40f2. I did not even know there is a metal hood for the 40f2 as mine is a rubber hood. Anyway, as I already have the M adapter, I did some quick shooting with the 28f2.8 & 40f2, with the 14-140 kit lens as a reference.
My quick impression is that the 40f2 is pretty good while the 28f2.8 is so so. Is that your experience with the Minolta lenses too? May be I should spend sometime to play with the M lenses instead of just focus on the Zeiss stuffs. Thanks.
Stephen, I purchased the Rokkor 40mm used because I was looking for a "fast-ish" lens in that focal length. Somewhere (I forget where -- RangeFinder Forum?) I'd already seen some comparisons between the Rokkor, the 40mm Summicron, and the Voigtlander f/1.4 Nokton, so I had some "reasonable" expectations, and was on the lookout for one of these three. A good deal on the Rokker presented itself first. The metal lens hood is after-market (Heavystar on eBay). The lens came with the standard collapsible rubber hood, but it had spent a little too much time collapsed.
I like the "character" of the Rokkor very much. Mine is the early version, a direct copy of the Summicron. It's certainly different than modern lenses - sharp enough, but not as "clinically crisp" in my opinion. I don't have a 40mm Voigtlander or Pen or Konica or Olympus OM to compare sharpness, bokeh, etc. at wider apertures, so I can only say that I like what I've seen so far. I haven't done any side-by-side tests with the native zooms; results would be somewhat moot as I didn't really buy the lens to use it at f/5.6 or f/8.
Other advantages of this lens are its small size, light weight (120g) and very good build quality. Disadvantage is minimum focusing distance.
Earlier, I'd read some posts that showed smearing and corner issues with some wider m-lenses, so I didn't even consider looking for a 28mm. The matching 90mm f/4 lens from the C-series can be found at resonable prices, but it's a bit too slow IMO. I'm considering the CV 75mm f/2.5 or 90mm Tele-Elmarit as good candidates for the "small" kit but, frankly, this focal length isn't a priority right now.