The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony FE 16-35mm F2.8 GM II and the Sigma 18-50mm F2.8-4.5 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. Sony FE 16-35mm F2.8 GM II is the longer of the two lenses at 112mm. The Sigma 18-50mm F2.8-4.5 DC OS HSM with a length of 89mm, is 23mm shorter. Besides being longer, the Sony FE 16-35mm F2.8 GM II also has a larger diameter of 88mm compared to the Sigma 18-50mm F2.8-4.5 DC OS HSM's 74mm 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 18-50mm F2.8-4.5 DC OS HSM weighs 395g, 27% (152g) lighter than the Sony FE 16-35mm F2.8 GM II's weight of 547g.
Filter Threads
The Sony FE 16-35mm F2.8 GM II has a filter size of 82mm whereas the Sigma 18-50mm F2.8-4.5 DC OS HSM has a 67mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 82mm filters that we recommend you to consider for the Sony FE 16-35mm F2.8 GM II:
And these are the 67mm filters that we recommend for the Sigma 18-50mm F2.8-4.5 DC OS HSM:
Lens Mounts
The Sony FE 16-35mm F2.8 GM II has the Sony E lens mount whereas the Sigma 18-50mm F2.8-4.5 DC OS HSM has the Sigma SA 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 Sigma SD1 Merrill, Sigma SD1 and for the Sigma SA Mount.
Sigma 18-50mm F2.8-4.5 DC OS HSM is also available in Canon EF , Pentax KAF3, Sony Alpha and Nikon F (DX) mounts.
Focal Range
Sony FE 16-35mm F2.8 GM II has a focal range of 16-35mm and
2.2X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
24 - 52.5mm.
On the other hand, the Sigma 18-50mm F2.8-4.5 DC OS HSM has a focal range of 18-50mm and 2.8X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-75mm when used on a APS-C / DX format camera.
