The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony 135mm F2.8 (T4.5) STF 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 135mm F2.8 (T4.5) STF is the longer of the two lenses at 99mm. The Sigma 85mm F1.4 EX DG HSM with a length of 88mm, is 11mm shorter. On the other hand, the Sigma 85mm F1.4 EX DG HSM has a larger diameter of 86mm compared to the Sony 135mm F2.8 (T4.5) STF's 80mm 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, 0% (5g) lighter than the Sony 135mm F2.8 (T4.5) STF's weight of 730g.
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 135mm F2.8 (T4.5) STF has a filter size of 72mm 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 72mm filters that we recommend you to consider for the Sony 135mm F2.8 (T4.5) STF:
And these are the 77mm filters that we recommend for the Sigma 85mm F1.4 EX DG HSM:
Lens Mounts
Both the Sony 135mm F2.8 (T4.5) STF 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 135mm F2.8 (T4.5) STF is a prime lens with fixed focal lenght of 135mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
202.5mm.
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.