The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 70mm F2.8 EX DG Macro and the Pentax FA 77mm 1.8 L 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 Pentax FA 77mm 1.8 L with a length of 48mm, is 47mm shorter. Besides being longer, the Sigma 70mm F2.8 EX DG Macro also has a larger diameter of 76mm compared to the Pentax FA 77mm 1.8 L's 64mm 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. Pentax FA 77mm 1.8 L weighs 270g, 48% (257g) lighter than the Sigma 70mm F2.8 EX DG Macro's weight of 527g.
Lens Mounts
Both the Sigma 70mm F2.8 EX DG Macro and the Pentax FA 77mm 1.8 L has the same Pentax KAF lens mount. Some of the latest released cameras that are compatible with the Pentax KAF lenses are Pentax K-3 III Mono, Pentax KF and Pentax K-3 III.
Sigma 70mm F2.8 EX DG Macro is also available in the Canon EF , Nikon F (FX), Sony Alpha and Sigma SA mounts.
Focal Range
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.
On the other hand, the Pentax FA 77mm 1.8 L is a prime lens with fixed focal lenght of 77mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 115.5mm.
