Canon EF 50mm f/1.4 USM
Let’s make it clear: this lens is the best 50mm choice among our 4 Canon-mount competitors, no matter the sensor size. It has the best definition of all the lenses displayed in these pages. Mounted on a 1Ds MkIII, it climbs to 63 lp/mm. No other lens-body couple listed here can outperform this. Moreover, this 50mm shows a very good MTF and has a very constant definition on the whole picture field. Vignetting is quite visible when fully opened, but almost disappears 2 stops later. Its only weakness, as with all the Canon lenses listed here, are that its chromatic aberrations are more noticeable than those for other brands.
The Canon EF 50 mm f/1.4 USM is the 50mm to have if you have a Canon body, no matter the sensor inside. It is a very sharp lens.
Canon EF 50mm f/1.2L USM
This is the most expensive 50mm among all our competitors. Unfortunately, however, it is not the most efficient as far as its metrics are concerned. Mounted on a 1Ds MkIII, this 50mm scores 10 lp/mm below the much cheaper 50mm f/1.4 USM. An analysis of the MTF chart also reveals another weakness of this lens, which does not manage to reach a balanced homogeneity on the whole field no matter how tight you close the lens. Moreover, the lens produces very dense chromatic aberrations.
Far from being the best on any Canon sensor, the Canon EF 50mm f1.2L USM 50mm is surpassed by most other lenses, and above all by the excellent 50mm f/1.4 USM.
Canon EF 50mm f/1.8II
As it was the case with the Nikon mount, Canon’s entry-level 50mm is also a tough competitor. If the others have a better pure resolution, this 50mm f1.8II proves very good in low-light conditions, reaching very good DxOMark scores at f/2.8 aperture. Mounted on a full-frame body, it has a slight tendency to produce too-soft edges. The problem is similar to that of the 50mm f1.2L USM, except for the price. And in fact, the 50mm f1/8II’s chromatic aberrations are well-contained. Mounted on an APS-C sensor, this 50mm shows the best definition, and its edges are much better. If they are too soft at f/2.8, closing 1 more stop produces a well-balanced image.
The Canon EF 50mm f/1.8 II is no match for the Cannon 50mm f/1.4 USM on a full-frame body, as the edges of the image may be too soft. On an APS-C sensor, however, it proves very good, especially at f/4.
Sigma 50mm f/1.4 EX DG HSM
Just like its Nikon-mount counterpart, this 50mm for Canon is a highly reliable lens, especially with respect to its central resolution. It reaches very good definition at f/2.8; moreover, it achieves its best DxOMark score fully opened. This is very good for a fast lens. But as it is the case with the Nikon mount, this 50mm shows some soft edges— softer than those for the Canon 50mm f/1.4 USM. Further, while the vignetting is well-contained, the chromatic aberrations are a bit strong.
An excellent performer on every Canon sensor, this Sigma is a perfect alternative if you want something other than the Canon EF 50mm f/1.4 USM.