It is almost impossible 4

I've been looking a long time for a suitable for me 50mm lens.
As light Strongest lens I have the Canon 85mm 1.2 L II.
These optics can be topped by none available on the market 85mm KB lens, whether Zeiss, Nikon and Sigma, have tested them all.
So I've looked at and the 50mm 1.2 Canon.
Also great and very sharp (in the middle).
For my (few) use but I think the price too high.

So the Canon 1.8 and 1.4 he tested Sigma. The 1.8-Canon he immediately works perfectly.
The 1,4-he was Sigma, as I so often was able to determine with Canon and Nikon, a failure. Time front, sometimes back focus, depending on your mood.
But now I have decided for the happy medium.

The Canon 50mm / 1.4.
Why:
The feel and the metal bayonet are significantly better than the 1.8-er Canon.
The focus is not really much better that the difference in price for 1,8-he would be dimmed soooo justified, but ........
The light intensity and better bokeh justify my opinion the higher price compared with the significantly cheaper 50mm 1.8.
With an output of 95% (compared to the Canon 50mm 1.2) Me a Preisunteschied of more than 1,100 euros, the choice was not difficult.
I use it mainly for the 1,4-edge panoramic shots and as easy on 'Device' on the 5D MKIII.

Dis sharpness is impressive already at open aperture and autofocus fits perfectly (I have a test photo 100% crop at full aperture added).
Dimmed at f / 5.6 to 8 not to do better.
However, one must also note that at full aperture the vignetting can be seen clearly.
This can, however, automatically in the Canon's Raw converter software fix (goes naturally with PS or LR exactly).

My Conclusion:
Anyone looking for a bright 50 mm lens and is not satisfied with the performance of a 50mm zoom lens, which should access here.