@Simsurace: the field curvature is bending backwards (i.e. you may have a sharp centered subject at some mid-distance, and corners at infinite sharp too).
I could do direct comparisons with the Sigma 24/1.4, indeed. Not had the opportunity so far. My first impressions (if memory serves well):
- The Sigma seems to have a flat field, and possibly a nicer daytime bokeh
- The Zeiss has the typical Zeiss rendering (high contrast, high color saturation). It seems more neutral than the warmish (yellowish) 50/2. It also seems to better handle night shots than the Sigma, despite a flare behaviour that is hard to predict (e.g. on a 3-lamp array near a corner, the central one would cause massive flare and the two others none at all). Its distortion, while low overall, is more conspicuous than Sigma's: barrel, but with a more pronounced center distortion, so the observer might notice it since the center seems to buldge.
Use case: Sigma: architecture, ambient or street (great subject isolation)
Zeiss: travel, night
Like all sharp short FL lenses, focussing the Zeiss manually is difficult; in critical cases, check on screen. Here the Sigma AF is helpful (after calibration).
By the way, what was it that put you off with the 25/2.8 ?
