The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Nikon 20mm f1.8G ED and the Sigma 10-20mm F3.5 EX DC 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 10-20mm F3.5 EX DC HSM is the longer of the two lenses at 88mm. The Nikon 20mm f1.8G ED with a length of 81mm, is 7mm shorter. Besides being longer, the Sigma 10-20mm F3.5 EX DC HSM also has a larger diameter of 87mm compared to the Nikon 20mm f1.8G ED's 83mm 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 20mm f1.8G ED weighs 355g, which means it is 165g (31%) lighter than the Sigma 10-20mm F3.5 EX DC HSM which has a weight of 520g.
Filter Threads
The Nikon 20mm f1.8G ED has a filter size of 77mm whereas the Sigma 10-20mm F3.5 EX DC HSM 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 77mm filters that we recommend you to consider for the Nikon 20mm f1.8G ED:
And these are the 82mm filters that we recommend for the Sigma 10-20mm F3.5 EX DC HSM:
Lens Mounts
Both the Nikon 20mm f1.8G ED and the Sigma 10-20mm F3.5 EX DC HSM has the same Nikon F (DX) lens mount. Some of the latest released cameras that are compatible with the Nikon F (DX) lenses are Nikon D6, Nikon D780 and Nikon D3500.
Sigma 10-20mm F3.5 EX DC HSM is also available in Canon EF , Pentax KAF3, Sony Alpha and Sigma SA mounts.
Focal Range
Nikon 20mm f1.8G ED is a prime lens with fixed focal lenght of 20mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
30mm.
On the other hand, the Sigma 10-20mm F3.5 EX DC HSM has a focal range of 10-20mm and 2.0X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 15-30mm when used on a APS-C / DX format camera.