As to the question about the 300mm...
The 300/4.5 is a very fascinating lens. It does not use internal-focus, so focusing isn't as quick and light as a more modern design, but that gives a pleasant trade-off as the bokeh is extremely pleasing and has no color fringing or donuty edges. The way the bokeh blooms, the lens acts as though it has an aperture far larger than 4.5 and is more like a 2.8.
The lens does exhibit a little purple fringing, so you will need to take that into account when photographing swans or something like that. For most wildlife and sports stuff, I'm using a Tokina AT-X 100-300/4 zoom which isn't as sharp wide-open, but is quicker to focus and doesn't fringe.
Excuse me, the purple fringe problem is usually only evident on crop-sensor DSLRs, not on film.
Where the 300/4.5 really shines is in portraiture. Man, is it beautiful. I Use it a lot on Four-Thirds bodies and it simpky rocks.