Upload & Sell: On
Interesting, JameelH. You can see that f5.6 is the strong suit of the older lens, and one can expect f8 to be similar.
[They are both here: http://www.zeissimages.com/mtf.php]
The CY records stellar (higher) 40 lpmm performance from image centre out to the short edges (12mm image height) at f5.6, thence the two lenses show different character, the CY keeps its tan/sag close together while declining steadily - the ZE/F lines separate, but stay higher. Well, one of them anyway.
Which is why I say its pretty much the same, unless your subject matter needs strong central performance - and I am prepared to say most images do, to put some perspective on the over-emphasis on corners lens enthusiasts fall victim to. So we see lens makers not particularly caring about minimising vignetting, despite the photozone site casting nasty looks at them.
Note also the lower MTF 40 lpmm the ZE shows at the image centre at f5.6 compared with its f2.8 effort, this is IMO the most striking doifference in these two lenses. The CY lens, by contrast (as it were), looks like a different lens at f5.6 compared with its f2.8 chart - *much better*. This looks like a design intent to me in the ZE, maybe Zeiss are channelling the bokeh fans on the ZE thread AhamB alludes to above!
I'd be interested to hear if you see CA or other odd behaviour in the ZE in the corners (15-20mm IH) on high contrast edges - the 40 lpmm lines are quite a distance apart out there at both reported apertures, whereas the CY has them almost as overlays at 20-21mm image height at f5.6, and does this very well for fine detail even wide open from 15-21mm - that is some achievement of course, in such a wide angle optic.
The A900 can now easily use the ZF version (Leitax) - but I won't be 'side-grading', for the above-stated reasons, plus the extra 100 grams of weight won't help. That's progress for you, though. But you do of course get a warranty, and a good chance of a good sample with a new lens. cheers, philip.