Despite the stellar MTF, the SEM 24 has a surprisingly heavy vignette, even compared to the ZE 21/2.8. It retains only 40% of illumination at f8 - which by the above image and the data sheets seems to be as good as it gets - whereas the ZE 21mm retains 70% at f5.6 and further improves at smaller apertures.
Noise shows up when low tones are lifted, of course, and we see variations in skies rather easily. I believe I would find it unacceptable because the vignette is stronger than the 21/2.8 at its frame edge by the image height of 12mm! And since it is a long slow increase to the vignette you get the effect of an APS-C lens on a full frame sensor. Thanks for posting..I just looked up the 21mm and 18mm SEM and they are the same or worse. You really would need to rely on excellent shadow lifting profiles for these to work acceptably.
Nov 23, 2013 at 10:51 PM
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