The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 28-75mm F2.8 Di III and the Tamron 45mm F1.8 Di VC USD 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 28-75mm F2.8 Di III is the longer of the two lenses at 118mm. The Tamron 45mm F1.8 Di VC USD with a length of 92mm, is 26mm shorter. On the other hand, the Tamron 45mm F1.8 Di VC USD has a larger diameter of 80mm compared to the Tamron 28-75mm F2.8 Di III's 76mm 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. Tamron 45mm F1.8 Di VC USD weighs 520g, 3% (20g) lighter than the Tamron 28-75mm F2.8 Di III's weight of 540g.
Filter Threads
Both the Tamron 28-75mm F2.8 Di III and the Tamron 45mm F1.8 Di VC USD 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 28-75mm F2.8 Di III has the Sony E lens mount whereas the Tamron 45mm F1.8 Di VC USD has the Nikon F (FX) lens mount. Some of the latest released cameras that are compatible with these mounts are Sony FX5, Sony A7R VI and Sony A7 V for the Sony E Mount and Nikon D6, Nikon D780 and Nikon D3500 for the Nikon F (FX) Mount.
Tamron 28-75mm F2.8 Di III is also available in the Sony E and Nikon Z mounts.
Tamron 45mm F1.8 Di VC USD is also available in Canon EF and Sony Alpha mounts.
Focal Range
Tamron 28-75mm F2.8 Di III has a focal range of 28-75mm and
2.7X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
42 - 112.5mm.
On the other hand, the 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.
