The Zeiss 16-35/2.8 arrived a few minutes ago. I whipped it out, stuck it on the second A900 I just bought for this summer's wedding schedule and zoomed around the house snapping anything I could.
Almost no CA at all even shooting edges against a completely whited out window ... a touch of barrel, but well controlled for a 16mm zoom, sharp corners ... again especially for a zoom. Zeiss color and contrast. Slight vignetting but very little IMO, not very dark so easily corrected if desired. Need for it to get sunny out to check flare.
Focuses very close, with the front element very close to the subject. Focuses quick, quiet and sure ... much better than my noisy old Zeiss/Contax N17-35/2.8, and the images look snappier (probably due to the A900 more than the optics).
Build quality is Zeiss all the way ... perfect mate to the 24-70/2.8.
Attached 4 shots done with the 16-35.
Expensive, but so far looks to be worth every penny.
Also picked up a Sony 500/8 mirror ... this is the only AF mirror I've ever seen. I knew that Minolta had made the Leica R 500 mirror, and liked the color rendition of that lens for certain subjects, but it was a bear to use ... on the A900 it's a whole new ballgame ... with SSS and AF this is a much more usable solution for that extra reach without a huge lens. Very nice color and contrast ... just like the Leica version.
Attached 1 shot with the 500 mirror...