Ive just sold my wide end, Right now my widest is 24mm. Im looking at buying the 12-24mm sigma - again... or even the 11-16mm toki. Also been looking at the 17-40mm.
Basically what else is there thats not 1000 +
Basically I was never happy with the 17-40 distortion & Corners, the zeiss 18 have huge flare and distortion probs. the only one I really liked of the above was the sigma but the corners was soft.
Have never tried the toki, or is there something else to consider.