The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron SP 35mm F1.4 Di USD and the Nikon Micro 40mm F2.8 for their suitability to various photography scenarios:
Size and Weight Comparison
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. Nikon Micro 40mm F2.8 weighs 235g, 70% (570g) lighter than the Tamron SP 35mm F1.4 Di USD's weight of 805g.
Lens Mounts
Both Tamron SP 35mm F1.4 Di USD has the Nikon F (FX) lens mount whereas the Nikon Micro 40mm F2.8 has the Nikon F (DX) lens mount. Some of the latest released cameras that are compatible with these mounts are Nikon D6, Nikon D780 and Nikon D3500 for the Nikon F (FX) Mount and Nikon D3500, Nikon D7500 and Nikon D5600 for the Nikon F (DX) Mount.
Tamron SP 35mm F1.4 Di USD is also available in Canon EF mount.
Focal Range
Tamron SP 35mm F1.4 Di USD is a prime lens with fixed focal lenght of 35mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides an 35mm (FF) equivalent of 52.5mm.
Nikon Micro 40mm F2.8 is a prime lens with fixed focal lenght of 40mm which has an effective (full-frame 35mm equivalent) focal range of 60mm when used on a APS-C / DX format camera.