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 70mm F2.8 EX DG Macro 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 70mm F2.8 EX DG Macro is the longer of the two lenses at 95mm. The Sony 85mm F2.8 SAM with a length of 52mm, is 43mm shorter. Besides being longer, the Sigma 70mm F2.8 EX DG Macro also has a larger diameter of 76mm 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 352g (66%) lighter than the Sigma 70mm F2.8 EX DG Macro which has a weight of 527g.
Lens Mounts
Both the Sony 85mm F2.8 SAM and the Sigma 70mm F2.8 EX DG Macro 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 70mm F2.8 EX DG Macro 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 70mm F2.8 EX DG Macro is a prime lens with fixed focal lenght of 70mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 105mm.