The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 85mm F1.8 VC and the Canon 400mm f2.8L IS II USM 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. Canon 400mm f2.8L IS II USM is the longer of the two lenses at 343mm. The Tamron 85mm F1.8 VC with a length of 91mm, is 252mm shorter. Besides being longer, the Canon 400mm f2.8L IS II USM also has a larger diameter of 163mm compared to the Tamron 85mm F1.8 VC's 85mm 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 85mm F1.8 VC weighs 700g, which means it is 3150g (81%) lighter than the Canon 400mm f2.8L IS II USM which has a weight of 3850g.
Filter Threads
The Tamron 85mm F1.8 VC has a filter size of 67mm whereas the Canon 400mm f2.8L IS II USM has a 52mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 67mm filters that we recommend you to consider for the Tamron 85mm F1.8 VC:
And these are the 52mm filters that we recommend for the Canon 400mm f2.8L IS II USM:
Lens Mounts
Both the Tamron 85mm F1.8 VC and the Canon 400mm f2.8L IS II USM 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.
Tamron 85mm F1.8 VC is also available in Sony Alpha and Nikon F (FX) mounts.
Focal Range
Tamron 85mm F1.8 VC is a prime lens with fixed focal lenght of 85mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
136mm.
On the other hand, the Canon 400mm f2.8L IS II USM is a prime lens with fixed focal lenght of 400mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 640mm.