The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony 300mm F2.8 G and the Sigma 85mm F1.4 EX DG HSM 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. Sony 300mm F2.8 G is the longer of the two lenses at 243mm. The Sigma 85mm F1.4 EX DG HSM with a length of 88mm, is 155mm shorter. Besides being longer, the Sony 300mm F2.8 G also has a larger diameter of 122mm compared to the Sigma 85mm F1.4 EX DG HSM's 86mm 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. Sigma 85mm F1.4 EX DG HSM weighs 725g, 68% (1585g) lighter than the Sony 300mm F2.8 G's weight of 2310g.
Below you can find the dimension and weight table of the Telephoto Prime Lenses in Sony Alpha Mount for size comparison purposes.
Telephoto Lenses in Sony Alpha Mount for Size Comparison
Filter Threads
The Sony 300mm F2.8 G has a filter size of 42mm whereas the Sigma 85mm F1.4 EX DG HSM has a 77mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 42mm filters that we recommend you to consider for the Sony 300mm F2.8 G:
And these are the 77mm filters that we recommend for the Sigma 85mm F1.4 EX DG HSM:
Lens Mounts
Both the Sony 300mm F2.8 G and the Sigma 85mm F1.4 EX DG HSM has the same Sony Alpha lens mount. Some of the latest released cameras that are compatible with the Sony Alpha lenses are Sony A99 II, Sony A68 and Sony A77 II.
Sigma 85mm F1.4 EX DG HSM is also available in Canon EF , Nikon F (FX), Pentax KAF3 and Sigma SA mounts.
Focal Range
Sony 300mm F2.8 G is a prime lens with fixed focal lenght of 300mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
450mm.
On the other hand, the Sigma 85mm F1.4 EX DG HSM is a prime lens with fixed focal lenght of 85mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 127.5mm.