Mon 11-Aug-08 11:57 AM | edited Mon 11-Aug-08 11:58 AM by cms
Yes, they are. Nikon uses the "G" to designate lenses without aperture rings.
Also the 10-20 has a smaller rear element designed to work only with the DX/APS size digital sensors and will thus give black corners when shot on 35mm flim (although it could possibly work fine at around 18mm and up).
Depends on what you're really doing. If you like shooting in manual and plan to shoot alot with it you probablly won't like it much. I usually shoot my f90x with older manual focus primes but sometimes I put put on a G style zoom from the digital kit if I want to shoot some action shots of something. I just shoot it in S mode for that and it makes no difference to me. If I were trying to use that as the main lens shooting landscapes, still life and things like that I'd probablly not like being limited to P and S mode though.