The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Pentax 15mm F4 ED AL L and the Sigma 15mm F2.8 EX DG Fisheye 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 15mm F2.8 EX DG Fisheye is the longer of the two lenses at 65mm. The Pentax 15mm F4 ED AL L with a length of 40mm, is 25mm shorter. Besides being longer, the Sigma 15mm F2.8 EX DG Fisheye also has a larger diameter of 74mm compared to the Pentax 15mm F4 ED AL L's 63mm 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 15mm F4 ED AL L weighs 189g, which means it is 181g (48%) lighter than the Sigma 15mm F2.8 EX DG Fisheye which has a weight of 370g.
Lens Mounts
Both the Pentax 15mm F4 ED AL L and the Sigma 15mm F2.8 EX DG Fisheye 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 Monochrome, Pentax KF and Pentax K-3 III.
Sigma 15mm F2.8 EX DG Fisheye is also available in Canon EF , Nikon F (FX), Sony Alpha and Sigma SA mounts.
Focal Range
Both lenses have the same focal range of
15mm but while Pentax 15mm F4 ED AL L has the fastest aperture of
F4.0, the Sigma 15mm F2.8 EX DG Fisheye's widest aperture value is
F2.8.