Hi there
Well, I haven't got there yet!
I've got the Sony 20mm f2.8 . . . . . and it's nice and small, but, the problem is that if you stop down beyond f8, then it isn't really that sharp . . and if you shoot faster than f8, then the corners aren't good. Added to which there is quite a lot of CA.

I've also got the Sigma 12-24, which, at around the same price, is a better bet. You still need to stop right down to get sharp corners . . but it doesn't seem to get softer in the middle. Maybe you could consider it as a 13-22 f8! Mind you, I'm not all that fussed about shooting wide open with WA lenses, but I do like them to be sharp.

I suppose the real truth is that, as long as it's comparable with the Nikon 14-24, the Zeiss 16-35 is going to be needed when it appears :-(

Still, all this doesn't detract from the fact that the A900 produces lovely, detailed files, Here are a few samples (without the pixel peeping crops).

The first two were taken with the 20mm Sony f2.8:

Here are a few with the Sigma 12-24:

Reaching out:

I was walking across the fields - a long long way from the nearest house, and in the middle of a field I found some scrubby willows, an overgrown pond and an old bench . . . . . and a rabbit on a post:

Closer examination made me wonder whether it might be a hare:

All pictures were shot RAW with daylight white balance, converted to DNG and processed in Aperture.

All except the first two were all taken just before sundown