[Photongraph]

Wer das Geld hat sollte zum Zeiss greifen. Das Sigma ist aber garantiert die günstigere Linse.

Aber ich mag mehr die Carl Zeiss T*-Vergütung, gibt schöne Kontraste und Farben. Auch ist das Zeiss 24-70mm wirklich sehr schnell, dank SSM. Das Fokusieren ist wirklich damit genial an der Alpha 900... Viel schneller als mit jedes Objektiv mit Stangen-AF.
Auch ist das Zeiss selbst bei Offenblende scharf.

Auch würde ich nicht bei dyxum völlig den Lesermeinungen vertrauen:

The manual-focusing ring's turning action is near-perfectly damped, though the zoom ring turns with a slight stiffness. AF action on our test camera, the Alpha 700, was rapid, sure, and -- thanks to the SSM -- practically silent. The side-mounted AF/MF switch is the largest and most easily operable of its type, at least that we've encountered. At 24mm, the lens cast a sliver of a shadow when used with the A700's built-in flash.

IN THE LAB

Not surprisingly for a Zeiss, sharpness and contrast scored in the SQF Excellent range. In DxO Analyzer 3.1 assessments of distortion control, we found only Slight barrel at 24mm (0.30%) and Imperceptible pincushion distortion at 50mm and 70mm (0.05 and 0.08%, respectively). Nada for light falloff at any tested focal length. And at the uniform close-focusing distance of approximately 13 inches, maximum magnification ratios ranged from 1:8.14 at 24mm to a strong 1:3.56 at 70mm.

CONCLUSIONS

Because this is a full-frame lens tested with an APS-sized sensor, we can't give the stellar distortion and light falloff results too much weight. (When Sony introduces its full-frame Alpha, we'll retest for distortion and light falloff.) That said, however, the lens' superior sharpness, extremely rugged construction, and satisfying macro performance all add up to an undeniable best-in-class showing for this impressive offspring of German and Japanese manufacturing know-how.

Quelle: http://www.popphoto.com/Reviews/Lens...ar-T-ZA-SSM-AF

http://www.popphoto.com/Reviews/Lens...ar-T-ZA-SSM-AF
http://www.popphoto.com/Reviews/Lens...M-AF-Lens-Test

http://photozone.de/sony-alpha-aps-c...470_28?start=1

Das Zeiss hat ganz klar die bessere optische Performance. Ist eben dafür teurer.