The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Carl Zeiss Planar T1,4/50 and the Canon 40mm f2.8 STM 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. Carl Zeiss Planar T1,4/50 is the longer of the two lenses at 69mm. The Canon 40mm f2.8 STM with a length of 22mm, is 47mm shorter. On the other hand, the Canon 40mm f2.8 STM has a larger diameter of 68mm 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. Canon 40mm f2.8 STM weighs 130g, 62% (220g) lighter than the Carl Zeiss Planar T1,4/50's weight of 350g.
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 Carl Zeiss Planar T1,4/50 and the Canon 40mm f2.8 STM 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.
Carl Zeiss Planar T1,4/50 is also available in Pentax KAF and Nikon F (FX) mounts.
Focal Range
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.
Canon 40mm f2.8 STM 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.