G1 with ZM21, 4.5 or 2.8?

[jim_buchanan]

Although I have a Elmarit M 28 to use on a G1, to give an effective 56mm lens, I wonder if I would prefer a wider "normal" as in the ZM 21, to give an effective 42mm.

The second part to this question is, those that have the ZM 21/4.5, is it fast enough for you, or would the f/2.8 be a benefit?

Thanks, for any comments.