The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 50mm F1.4 DG HSM A and the Sigma 17-50mm F2.8 EX DC OS HSM 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 50mm F1.4 DG HSM A is the longer of the two lenses at 100mm. The Sigma 17-50mm F2.8 EX DC OS HSM with a length of 92mm, is 8mm shorter. Besides being longer, the Sigma 50mm F1.4 DG HSM A also has a larger diameter of 85mm compared to the Sigma 17-50mm F2.8 EX DC OS HSM's 84mm 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 17-50mm F2.8 EX DC OS HSM weighs 565g, 30% (250g) lighter than the Sigma 50mm F1.4 DG HSM A's weight of 815g.
Filter Threads
Both the Sigma 50mm F1.4 DG HSM A and the Sigma 17-50mm F2.8 EX DC OS HSM have the same Filter thread size of 77mm.
Below are links to the 77mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Sigma 50mm F1.4 DG HSM A and the Sigma 17-50mm F2.8 EX DC OS HSM has the same Sigma SA lens mount. Some of the latest released cameras that are compatible with the Sigma SA lenses are Sigma Quattro, Sigma Quattro H and Sigma SD1 Merrill.
Sigma 50mm F1.4 DG HSM A is also available in the Canon EF , Sony Alpha, Nikon F (FX) and Leica L mounts.
Sigma 17-50mm F2.8 EX DC OS HSM is also available in Canon EF , Pentax KAF3, Sony Alpha and Nikon F (DX) mounts.
Focal Range
Sigma 50mm F1.4 DG HSM A is a prime lens with fixed focal lenght of 50mm.
On the other hand, the Sigma 17-50mm F2.8 EX DC OS HSM has a focal range of 17-50mm and 2.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 25.5-75mm when used on a APS-C / DX format camera.
