When I got a cheap used copy of the Sigma 20/1.8, I didn't expect much. But on a recent trip to Berlin, it surprised me with its quick low-light focus (on the 5D) and ability to capture city night scenes. Here are four samples:
Nordlys, there is very little distortion overall and even the edges are quite good. Sharpness in the corners is better than what I've seen with my 16-35L II (since sold). The only thing I don't care for is the bokeh wide open, even though very close focusing is possible.
Thanks for looking, Ben
I had this lens once, but only used it on 1.6X bodies. Always wondered how it would perform on full frame. In particular I loved it's close focusing ability - it allowed for some really interesting perspective shots. And on full frame I'd imagine ithe effects would be even more dramatic.
Looks to be a nice lens for FF. As Ben mentioned, though, the bokeh definitely leaves something to be desired. That's sort of an anomaly, though, as I've found most of Sigma's lenses to have very nice bokeh (my 30 f/1.4 and 150 f/2.8 macro both have outstanding bokeh).
Makten, some distortion is optically inevitable with wideangle lenses, but in comparative terms the 20/1.8 is quite good. None of the pics I posted was cropped, so you can judge for yourself (in fact, the first pic of the hotel lobby shows some distortion, especially on the left side).
