The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 50-100mm F1.8 A and the Sigma 50mm F1.4 DG HSM A for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is an important deciding factor when comparing two lenses. Sigma 50-100mm F1.8 A is the longer of the two lenses at 171mm. The Sigma 50mm F1.4 DG HSM A with a length of 100mm, is 71mm shorter. Besides being longer, the Sigma 50-100mm F1.8 A also has a larger diameter of 94mm compared to the Sigma 50mm F1.4 DG HSM A's 85mm diameter.
The weight of a lens is as important as its external dimensions, especially if you are planning to hand hold your camera and lens combination for longer periods. Sigma 50mm F1.4 DG HSM A weighs 815g, 45% (675g) lighter than the Sigma 50-100mm F1.8 A's weight of 1490g.
Lens Mounts
Both the Sigma 50-100mm F1.8 A and the Sigma 50mm F1.4 DG HSM A has the same Sigma SA lens mount. Some of the latest released cameras that are compatible with the Sigma SA lenses are Sigma SD1 Merrill, Sigma SD1 and .
Sigma 50-100mm F1.8 A is also available in Canon EF and Nikon F (DX) mounts.
Sigma 50mm F1.4 DG HSM A is also available in Canon EF , Sony Alpha, Nikon F (FX) and Leica L mounts.
Focal Range
Sigma 50-100mm F1.8 A has a focal range of 50-100mm and 2.0X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 75-150mm when used on a APS-C / DX format camera. Sigma 50mm F1.4 DG HSM A is a prime lens with fixed focal lenght of 50mm.