In article <32075E3C.49BD@interaccess.com>, hartmann@interaccess.com says...

>I am trying to identify which F3 focusing screen will maximize my
>ability to focus accurately in low light. Background: I intend to use
>the F3 only with lenses in the range 24-105 mm, with a minimum viewing
>aperture of f/2.8, in other words fast wide-angle to short-tele prime
>lenses. These are likely to be used quite often at or close to their
>maximum apertures, so accurate focusing is a must.

Hmmm, first, I would not use the 24's wider than f5.6, if possible
(slow shutter speeds are OK with a 24mm....). The "B" and "E" screens
are my favorites for the F3. The "D" is potentially sharper (having
no Fresnel lens), but the "B" and "E" also do not have the Fresnel
lens in a very small area in the center of the screen, the Fresnel
in the rest of the screen does not appear to affect sharpness, and
the "D" screen is quite uneven in illumination (very dark in the
corners) with short lenses - it is barely acceptable with a 50mm,
unacceptable with a 24mm. Even though the "G" screens are clear, they surprisingly do not appear much brighter than the "B" and "E" screens,
and I find Nikon microprism focus "aids" unuseable - and that is all
there is to focus with. They are also very uneven in illumination when
not matched to the taking lens FL. I am not familiar with the "U" screen.
F4 screens will fit the F3 and are slightly brighter - it might be worth trying (though they may not appear quite as sharp as F3 screens - I don't know [there is often a trade-off in screens between brightness, contrast,
sharpness, and illumination evenness]). BTW, I do a lot of low-light photography - the "B" screen works well for me (the "E" is the same,
but with grid lines added).
Hope This Helps

>I already use a "B" screen (matte fresnel only) on an FM2, and that is
>definitely better than the standard split image/microprism screen. But
>what about the other alternatives:
>"D" ("fine matte"): would this be any better than the "B"?
>"G1" - "G4": These are described as "clear Fresnel," but what's the
>improvement over the "B"?
>"U": again, what's the difference between this and "B".
>If anyone has _direct_ experience with an F3 and any or all of the above
>screens, I would appreciate your input.