I'm going to do in the next time day even more detailed tests, but advance has to be said before, the lens is like the others their worth 750 euros. Many say yes, the focus would be slower than in the 50's or so. The first test I could find with nieces slower focus behavior.
Sigma also seems better to pay attention to adjustment and increased quality control. During my first lenses still had a front focus, has the 24er (and the last week bought 35mm) no focal weakness. (See picture - the focus map, freehand with ISO1600 - 1.4 - 1 / 100s at 5DM3)
Furthermore, for me to mention the positive filter diameter of 77mm. It facilitates my use of neutral density filters, etc., since I can concomitantly from my 50mm. Saves money and space in your backpack.
(Preliminary) conclusion:
Who have long studied a 24er, is well served with Sigma. I had the 24L Canon times tested and it has not delivered better visually.
