The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 100-400mm F5-6.3 DG OS HSM and the Sigma 50-100mm F1.8 A 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 100-400mm F5-6.3 DG OS HSM is the longer of the two lenses at 182mm. The Sigma 50-100mm F1.8 A with a length of 171mm, is 11mm shorter. On the other hand, the Sigma 50-100mm F1.8 A has a larger diameter of 94mm compared to the Sigma 100-400mm F5-6.3 DG OS HSM's 86mm 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 100-400mm F5-6.3 DG OS HSM weighs 1160g, which means it is 330g (22%) lighter than the Sigma 50-100mm F1.8 A which has a weight of 1490g.
Filter Threads
The Sigma 100-400mm F5-6.3 DG OS HSM has a filter size of 67mm whereas the Sigma 50-100mm F1.8 A has a 82mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 67mm filters that we recommend you to consider for the Sigma 100-400mm F5-6.3 DG OS HSM:
And these are the 82mm filters that we recommend for the Sigma 50-100mm F1.8 A:
Lens Mounts
Both the Sigma 100-400mm F5-6.3 DG OS HSM and the Sigma 50-100mm F1.8 A 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 100-400mm F5-6.3 DG OS HSM is also available in Nikon F (FX) and Canon EF mounts.
Sigma 50-100mm F1.8 A is also available in Canon EF and Nikon F (DX) mounts.
Focal Range
Sigma 100-400mm F5-6.3 DG OS HSM has a focal range of 100-400mm and
4.0X zoom ratio .
On the other hand, the 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.