The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 17-70mm F2.8-4 DC OS HSM and the Nikon 24-85mm F3.5-4.5G ED VR 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 17-70mm F2.8-4 DC OS HSM is the longer of the two lenses at 89mm. The Nikon 24-85mm F3.5-4.5G ED VR with a length of 82mm, is 7mm shorter. Besides being longer, the Sigma 17-70mm F2.8-4 DC OS HSM also has a larger diameter of 79mm compared to the Nikon 24-85mm F3.5-4.5G ED VR's 78mm 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. Nikon 24-85mm F3.5-4.5G ED VR weighs 485g, 6% (35g) lighter than the Sigma 17-70mm F2.8-4 DC OS HSM's weight of 520g.
Filter Threads
Both the Sigma 17-70mm F2.8-4 DC OS HSM and the Nikon 24-85mm F3.5-4.5G ED VR have the same Filter thread size of 72mm.
Below are links to the 72mm filters that we recommend you to consider for these lenses:
Lens Mounts
The Sigma 17-70mm F2.8-4 DC OS HSM has the Nikon F (DX) lens mount whereas the Nikon 24-85mm F3.5-4.5G ED VR has the Nikon F (FX) lens mount. Some of the latest released cameras that are compatible with these mounts are Nikon D3500, Nikon D7500 and Nikon D5600 for the Nikon F (DX) Mount and Nikon D6, Nikon D780 and Nikon D3500 for the Nikon F (FX) Mount.
Sigma 17-70mm F2.8-4 DC OS HSM is also available in the Canon EF , Pentax KAF3, Sony Alpha and Sigma SA mounts.
Focal Range
Sigma 17-70mm F2.8-4 DC OS HSM has a focal range of 17-70mm and
4.1X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
25.5-105mm when used on a APS-C / DX format camera.
On the other hand, the Nikon 24-85mm F3.5-4.5G ED VR has a focal range of 24-85mm and 3.5X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 36 - 127.5mm.