The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony 85mm F2.8 SAM and the Sigma 300mm F2.8 APO 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. Sigma 300mm F2.8 APO EX DG HSM is the longer of the two lenses at 215mm. The Sony 85mm F2.8 SAM with a length of 52mm, is 163mm shorter. Besides being longer, the Sigma 300mm F2.8 APO EX DG HSM also has a larger diameter of 119mm compared to the Sony 85mm F2.8 SAM's 70mm 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. Sony 85mm F2.8 SAM weighs 175g, which means it is 2225g (92%) lighter than the Sigma 300mm F2.8 APO EX DG HSM which has a weight of 2400g.
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 85mm F2.8 SAM has a filter size of 55mm whereas the Sigma 300mm F2.8 APO EX DG HSM has a 46mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 55mm filters that we recommend you to consider for the Sony 85mm F2.8 SAM:
And these are the 46mm filters that we recommend for the Sigma 300mm F2.8 APO EX DG HSM:
Lens Mounts
Both the Sony 85mm F2.8 SAM and the Sigma 300mm F2.8 APO 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 300mm F2.8 APO EX DG HSM is also available in Canon EF , Nikon F (FX), Pentax KAF and Sigma SA mounts.
Focal Range
Sony 85mm F2.8 SAM 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.
On the other hand, the Sigma 300mm F2.8 APO EX DG HSM 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.