Originally posted by ogl Old FA20/2.8 and FA28/2.8 are not stellar lenses...It must be radically upgraded to be good at FF 36-50 MP cameras...
I had F28/2.8 which was better than FA28, but I can't say that it's really something special and very sharp...FA20 is even worse than F28...
I have had an FA20/2.8 for a number of years. While I agree with your description of it being "not stellar", it also didn't have a price to match that, although it has been regarded highly enough by sufficient numbers of people to maintain a good resale price, even with other offerings like the DA21, in the APS-C era. Stopped down, even a little, it provides good IQ.
If you want something in this focal length with stellar IQ, you have to be prepared to pay for it. A focal length of 20mm presents a challenge to the designer, though probably less so for a DSLR than a short-registration mirrorless design, but even so anything worthy of a DFA* rating is going to have a more limited market, due to its inevitably high price. Ricoh could do worse than to revamp some of its better existing film-era lenses with HD coatings, more (and/or rounder) aperture blades and Quick-shift, and run them as a second-tier lens range. I understand that both Nikon and Canon have a few older lenses in their lineups, though I'm not sure if they've been in any way updated.
New designs with WR and inbuilt AF drives should be designed for the DFA* line, at least at this time.