The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 10-24mm f3.5-4.5 II LD 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. Tamron 10-24mm f3.5-4.5 II LD is the longer of the two lenses at 84mm. The Sigma 15mm F2.8 EX DG Fisheye with a length of 65mm, is 19mm shorter. Besides being longer, the Tamron 10-24mm f3.5-4.5 II LD also has a larger diameter of 83mm compared to the Sigma 15mm F2.8 EX DG Fisheye's 74mm 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 15mm F2.8 EX DG Fisheye weighs 370g, 8% (36g) lighter than the Tamron 10-24mm f3.5-4.5 II LD's weight of 406g.
Lens Mounts
Both the Tamron 10-24mm f3.5-4.5 II LD 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 Mono, Pentax KF and Pentax K-3 III.
Tamron 10-24mm f3.5-4.5 II LD is also available in the Canon EF , Nikon F (DX), Sony Alpha and Canon EF mounts.
Sigma 15mm F2.8 EX DG Fisheye is also available in Canon EF , Nikon F (FX), Sony Alpha and Sigma SA mounts.
Focal Range
Tamron 10-24mm f3.5-4.5 II LD has a focal range of 10-24mm and
2.4X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
15-36mm when used on a APS-C / DX format camera.
On the other hand, the Sigma 15mm F2.8 EX DG Fisheye is a prime lens with fixed focal lenght of 15mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 22.5mm.
