The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 20mm F2.8 Di III OSD M1:2 and the Sony E 10-18mm F4 OSS for their suitability to various photography scenarios:
Size and Weight Comparison
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. Tamron 20mm F2.8 Di III OSD M1:2 weighs 220g, which means it is 5g (2%) lighter than the Sony E 10-18mm F4 OSS which has a weight of 225g.
Filter Threads
The Tamron 20mm F2.8 Di III OSD M1:2 has a filter size of 67mm whereas the Sony E 10-18mm F4 OSS 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 Tamron 20mm F2.8 Di III OSD M1:2:
And these are the 62mm filters that we recommend for the Sony E 10-18mm F4 OSS:
Lens Mounts
Both the Tamron 20mm F2.8 Di III OSD M1:2 and the Sony E 10-18mm F4 OSS has the same Sony E lens mount. Some of the latest released cameras that are compatible with the Sony E lenses are Sony FX5, Sony A7R VI and Sony A7 V.
Focal Range
Tamron 20mm F2.8 Di III OSD M1:2 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 Sony E 10-18mm F4 OSS has a focal range of 10-18mm and 1.8X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 15-27mm when used on a APS-C / DX format camera.
