The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 20-40mm F2.8 VXD and the Tamron 11-20mm F2.8 Di III-A for their suitability to various photography scenarios:
Size and Weight Comparison
Below you can find a scaled side-by-side image of Tamron 20-40mm F2.8 VXD and Tamron 11-20mm F2.8 Di III-A to get a better idea of how their sizes compare in real life.
Comparison image of the Tamron 20-40mm F2.8 VXD and the Tamron 11-20mm F2.8 Di III-A Size and Weight The weight of a lens is as important as its external dimensions, especially if you are planning to hand hold your camera and lens combination for longer periods. Tamron 11-20mm F2.8 Di III-A weighs 335g, 8% (30g) lighter than the Tamron 20-40mm F2.8 VXD's weight of 365g.
Below you can find the dimension and weight table of the Wideangle Zoom Lenses in Sony E Mount for size comparison purposes.
Wideangle Zoom Lenses in Sony E Mount for Size Comparison
Lens Mounts
Both the Tamron 20-40mm F2.8 VXD and the Tamron 11-20mm F2.8 Di III-A has the same Sony E lens mount. Some of the latest released cameras that are compatible with the Sony E lenses are Sony ZV-E1, Sony A7R V and Sony FX30.
Tamron 11-20mm F2.8 Di III-A is also available in Fujifilm X mount.
Focal Range
Tamron 20-40mm F2.8 VXD has a focal range of 20-40mm and 2.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 30 - 60mm.
Tamron 11-20mm F2.8 Di III-A has a focal range of 11-20mm and 1.8X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 16.5 - 30mm.