The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 45mm F1.8 Di VC USD and the Nikon 18-70mm f3.5-4.5G ED-IF for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is a crucial factor to consider when comparing two lenses. Tamron 45mm F1.8 Di VC USD is the longer of the two lenses at 92mm. The Nikon 18-70mm f3.5-4.5G ED-IF with a length of 76mm, is 16mm shorter. Besides being longer, the Tamron 45mm F1.8 Di VC USD also has a larger diameter of 80mm compared to the Nikon 18-70mm f3.5-4.5G ED-IF's 73mm diameter.
The weight of a lens is equally significant as its external dimensions, particularly if you intend to handhold your camera and lens combination for extended periods. Nikon 18-70mm f3.5-4.5G ED-IF weighs 420g, 19% (100g) lighter than the Tamron 45mm F1.8 Di VC USD's weight of 520g.
Filter Threads
Both the Tamron 45mm F1.8 Di VC USD and the Nikon 18-70mm f3.5-4.5G ED-IF have the same Filter thread size of 67mm.
Below are links to the 67mm filters that we recommend you to consider for these lenses:
Lens Mounts
The Tamron 45mm F1.8 Di VC USD has the Nikon F (FX) lens mount whereas the Nikon 18-70mm f3.5-4.5G ED-IF 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 45mm F1.8 Di VC USD is also available in the Canon EF and Sony Alpha mounts.
Focal Range
Tamron 45mm F1.8 Di VC USD is a prime lens with fixed focal lenght of 45mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
67.5mm.
On the other hand, the Nikon 18-70mm f3.5-4.5G ED-IF has a focal range of 18-70mm and 3.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-105mm when used on a APS-C / DX format camera.
