1. The best overall focusing screen for the F/F2 is the P; fan favorites are the G and H series; minimalists prefer the B; traditionalists, the K; my personal favorite is the E. Basically, collect as many screens as you can and have fun trying them out.
2. If I had to choose between the F3 and F4, I'd choose the F4 every time, but that's just me. The F4 isn't handicapped in any way when it comes to manually focusing. In fact, one could argue the F4 is superior in this regard because of its electronic rangefinder. For others, the electronic rangefinder in the F4 is the antichrist (it does have a tendency to blink in your eye).
3. I haven't tried the VC 20mm, but it's probably a better performer than the old Nikkors. That's not to say it's necessarily a better lens or that it takes better pictures. It most likely will simply have a different look with maybe a hair of extra "sharpness" in the extreme corners. I use an 18mm but if I were to get an F-mount 20mm right now, it'd be the 20mm f/4. But that's just me.
Last edited by LJSLATER; 12-02-2012 at 08:24 AM. Click to view previous post history.