The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 300mm F2.8 APO EX DG HSM 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 300mm F2.8 APO EX DG HSM is the longer of the two lenses at 215mm. The Pentax FA 77mm 1.8 L with a length of 48mm, is 167mm shorter. Besides being longer, the Sigma 300mm F2.8 APO EX DG HSM also has a larger diameter of 119mm 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, 88% (2130g) lighter than the Sigma 300mm F2.8 APO EX DG HSM's weight of 2400g.
Below you can find the dimension and weight table of the Telephoto Prime Lenses in Pentax KAF Mount for size comparison purposes.
Telephoto Lenses in Pentax KAF Mount for Size Comparison
Filter Threads
The Sigma 300mm F2.8 APO EX DG HSM has a filter size of 46mm whereas the Pentax FA 77mm 1.8 L has a 49mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 46mm filters that we recommend you to consider for the Sigma 300mm F2.8 APO EX DG HSM:
And these are the 49mm filters that we recommend for the Pentax FA 77mm 1.8 L:
Lens Mounts
Both the Sigma 300mm F2.8 APO EX DG HSM 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 300mm F2.8 APO EX DG HSM is also available in the Canon EF , Nikon F (FX), Sony Alpha and Sigma SA mounts.
Focal Range
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.
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.
