This I know. It isn't an issue of the AF being the top notch, but given >that F4 was the flagship at one point, and a LOT of people used it, the AF >can't be *that* bad, all things considered.
The F-4 was Nikon's first AF pro body. The AF is primitive compared to current top of the line models. It is also IIRC Nikon's heaviest film body, however the sealing and duty cycle are pro caliber. Nikon lenses also have a certain look to them, high acutance but not always pleasing bokeh. I would sit down and decide which features are most important to you. If the sealing and duty cycle is the F-4 may still be your best option though a used F-100 might suit your needs and has a faster AF. The PZ-1p is the most pro speced Pentax AF body and it has a good reputation for being dependable, but it is not sealed, has no PC socket and uses a lithium battery. If you can live with those features I would go with the Pentax as you already have some MF lenses, having an all manual back up body is very handy (K-1000) and you may find especially with wide angles that you're happy with MF. Also $500 sound steep for a PZ-1p. I bought my Z-1p in mint condition for $300 (thanks again Leon) and have been very happy with it. I would think with a little perseverance you could find one in that price range too. Butch Each man had only one genuine vocation - to find the way to himself. Hermann Hesse (Demian)
