Get the Sigma 24mm f/1.4 DG HSM Art or Canon 24mm at B&H Photo.
This 4-way shootout utilizes a subject that allows a good examination of sharpness and contrast (fine wood detail), field curvature, color correction and distortion.
Three primes, one zoom, all 24mm. In DAP:
Shootout: vs Canon 24/1.4L II, 24/2.8, 11-12/4L (Canon 5DM Mark II)
Presented with HD and UltraHD images, along with large crops from f/1.4 - f/13.
See also review of the Canon 24mm f/1.4L II and review of the Canon 24/2.8 IS and review of the Canon 11-24mm f/4L.
f1.4 @ 1/200 sec, ISO 100; 2015-03-26 17:47:53[low-res image for bot]
Canon EOS 5D Mark III + Sigma 24mm f/1.4 DG HSM Art