Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Carl Zeiss Distagon T2/25 is the longer of the two lenses at 98mm. The Schneider PC 28mm f2.8 with a length of 89mm is 9mm shorter. On the other hand, the Schneider PC 28mm f2.8 has a larger diameter of 75mm compared to Carl Zeiss Distagon T2/25's 73mm diameter.
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. Schneider PC 28mm f2.8 weighs 565g, 6% (35g) lighter than the Carl Zeiss Distagon T2/25's weight of 600g.
Lens Mounts
Both Carl Zeiss Distagon T2/25 and Schneider PC 28mm f2.8 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 Distagon T2/25 is also available in Nikon F (FX) mount.
Schneider PC 28mm f2.8 is also available in Pentax KAF , Sony Alpha and Nikon F (FX) mounts.
Focal Range
Carl Zeiss Distagon T2/25 is a prime lens with fixed focal lenght of 25mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides an 35mm (FF) equivalent of 40mm.
Schneider PC 28mm f2.8 is a prime lens with fixed focal lenght of 28mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides an 35mm (FF) equivalent of 44.8mm.