The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 40mm F1.4 DG HSM A and the Carl Zeiss Planar T1,4/50 for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is an important deciding factor when comparing two lenses. Sigma 40mm F1.4 DG HSM A is the longer of the two lenses at 131mm. The Carl Zeiss Planar T1,4/50 with a length of 69mm, is 62mm shorter. Besides being longer, the Sigma 40mm F1.4 DG HSM A also has a larger diameter of 88mm compared to the Carl Zeiss Planar T1,4/50's 66mm diameter.
The weight of a lens is as important as its external dimensions, especially if you are planning to hand hold your camera and lens combination for longer periods.
Below you can find the dimension and weight table of the Standard Prime Lenses in Canon EF Mount for size comparison purposes.
Standard Prime Lenses in Canon EF Mount for Size Comparison
Lens Mounts
Both the Sigma 40mm F1.4 DG HSM A and the Carl Zeiss Planar T1,4/50 has the same Canon EF lens mount. Some of the latest released cameras that are compatible with the Canon EF lenses are Canon 1D X III, Canon 6D MII and Canon 5D MIV.
Sigma 40mm F1.4 DG HSM A is also available in Nikon F (FX) , Sigma SA, Sony E and Leica L mounts.
Carl Zeiss Planar T1,4/50 is also available in Pentax KAF and Nikon F (FX) mounts.
Focal Range
Sigma 40mm F1.4 DG HSM A is a prime lens with fixed focal lenght of 40mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 64mm.
Carl Zeiss Planar T1,4/50 is a prime lens with fixed focal lenght of 50mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 80mm.