Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Zeiss Milvus 25mm F1.4 is the longer of the two lenses at 123mm. The Carl Zeiss Distagon T2,8/21 with a length of 109mm is 14mm shorter. Besides being longer, the Zeiss Milvus 25mm F1.4 also has a larger diameter of 95mm compared to Carl Zeiss Distagon T2,8/21's 87mm 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. Carl Zeiss Distagon T2,8/21 weighs 600g, 104% (625g) lighter than the Zeiss Milvus 25mm F1.4's weight of 1225g.
Below you can find the dimension and weight table of the 'Wideangle Prime Lenses in Nikon F (FX) Mount for size comparison purposes.
Wideangle Prime Lenses in Nikon F (FX) Mount for Size Comparison
Lens Mounts
Both Zeiss Milvus 25mm F1.4 and Carl Zeiss Distagon T2,8/21 has the same Nikon F (FX) lens mount. Some of the latest released cameras that are compatible with the Nikon F (FX) lenses are Nikon D6, Nikon D780 and Nikon D3500.
Zeiss Milvus 25mm F1.4 is also available in Canon EF mount.
Carl Zeiss Distagon T2,8/21 is also available in Canon EF and Pentax KAF mounts.
Focal Range
Zeiss Milvus 25mm F1.4 is a prime lens with fixed focal lenght of 25mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides an 35mm (FF) equivalent of 37.5mm.
Carl Zeiss Distagon T2,8/21 is a prime lens with fixed focal lenght of 21mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides an 35mm (FF) equivalent of 31.5mm.