The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 28-70mm F2.8 DG DN and the Sigma 105mm F2.8 EX DG 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 105mm F2.8 EX DG OS HSM is the longer of the two lenses at 127mm. The Sigma 28-70mm F2.8 DG DN with a length of 102mm, is 25mm shorter. Besides being longer, the Sigma 105mm F2.8 EX DG OS HSM also has a larger diameter of 78mm compared to the Sigma 28-70mm F2.8 DG DN's 72mm 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 28-70mm F2.8 DG DN weighs 470g, which means it is 256g (35%) lighter than the Sigma 105mm F2.8 EX DG OS HSM which has a weight of 726g.
Filter Threads
The Sigma 28-70mm F2.8 DG DN has a filter size of 67mm whereas the Sigma 105mm F2.8 EX DG OS HSM has a 62mm 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 28-70mm F2.8 DG DN:
And these are the 62mm filters that we recommend for the Sigma 105mm F2.8 EX DG OS HSM:
Lens Mounts
The Sigma 28-70mm F2.8 DG DN has the Sony E lens mount whereas the Sigma 105mm F2.8 EX DG OS HSM has the Canon EF lens mount. Some of the latest released cameras that are compatible with these mounts are Sony FX5, Sony A7R VI and Sony A7 V for the Sony E Mount and Blackmagic URSA 12K LF, Z CAM E2-F6 II 6K and Z CAM E2-S6 II 6K for the Canon EF Mount.
Sigma 105mm F2.8 EX DG OS HSM is also available in Sigma SA and Nikon F (FX) mounts.
Focal Range
Sigma 28-70mm F2.8 DG DN has a focal range of 28-70mm and
2.5X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
42 - 105mm.
On the other hand, the Sigma 105mm F2.8 EX DG OS HSM is a prime lens with fixed focal lenght of 105mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 168mm.
