The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony E 20mm F2.8 and the Sigma 19mm F2.8 EX DN 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 19mm F2.8 EX DN is the longer of the two lenses at 46mm. The Sony E 20mm F2.8 with a length of 20mm, is 26mm shorter. On the other hand, the Sony E 20mm F2.8 has a larger diameter of 63mm compared to the Sigma 19mm F2.8 EX DN's 61mm 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. Sony E 20mm F2.8 weighs 69g, which means it is 71g (50%) lighter than the Sigma 19mm F2.8 EX DN which has a weight of 140g.
Below you can find the dimension and weight table of the Wideangle Prime Lenses in Sony E Mount for size comparison purposes.
Wideangle Lenses in Sony E Mount for Size Comparison
Filter Threads
The Sony E 20mm F2.8 has a filter size of 49mm whereas the Sigma 19mm F2.8 EX DN has a 46mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 49mm filters that we recommend you to consider for the Sony E 20mm F2.8:
And these are the 46mm filters that we recommend for the Sigma 19mm F2.8 EX DN:
Lens Mounts
Both the Sony E 20mm F2.8 and the Sigma 19mm F2.8 EX DN has the same Sony E lens mount. Some of the latest released cameras that are compatible with the Sony E lenses are Sony A6700, Sony FX30 and Sony ZV-E10.
Sigma 19mm F2.8 EX DN is also available in Micro Four Thirds mount.
Focal Range
Sony E 20mm F2.8 is a prime lens with fixed focal lenght of 20mm which has an effective (full-frame 35mm equivalent) focal range of
30mm when used on a APS-C / DX format camera.
On the other hand, the Sigma 19mm F2.8 EX DN is a prime lens with fixed focal lenght of 19mm which has an effective (full-frame 35mm equivalent) focal range of 28.5mm when used on a APS-C / DX format camera.