The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Pentax-D FA 85mm F1.4 ED SDM AW 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. Pentax-D FA 85mm F1.4 ED SDM AW is the longer of the two lenses at 124mm. The Sigma 70mm F2.8 EX DG Macro with a length of 95mm, is 29mm shorter. Besides being longer, the Pentax-D FA 85mm F1.4 ED SDM AW also has a larger diameter of 95mm compared to the Sigma 70mm F2.8 EX DG Macro's 76mm 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 70mm F2.8 EX DG Macro weighs 527g, 58% (728g) lighter than the Pentax-D FA 85mm F1.4 ED SDM AW's weight of 1255g.
Lens Mounts
The Pentax-D FA 85mm F1.4 ED SDM AW has the Pentax KAF4 lens mount whereas the Sigma 70mm F2.8 EX DG Macro has the Sigma SA lens mount. Some of the latest released cameras that are compatible with these mounts are , and for the Pentax KAF4 Mount and Sigma Quattro, Sigma Quattro H and Sigma SD1 Merrill for the Sigma SA Mount.
Sigma 70mm F2.8 EX DG Macro is also available in Canon EF , Nikon F (FX), Pentax KAF and Sony Alpha mounts.
Focal Range
Pentax-D FA 85mm F1.4 ED SDM AW 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.