Tamron 11-20mm F2.8 Di III-A RXD Review
Launched in April 2021, the Tamron 11-20mm F2.8 Di III-A RXD is a fast ultra-wide-angle zoom lens with a constant F2.8 aperture throughout the focal range.
This Tamron lens is designed for Sony E-mount APS-C sensor mirrorless cameras, such as the flagship A6600. You can also use it with full-frame Sony Alpha models, just so long as you set them to APS-C crop mode.
It's officially the world's first ever F2.8 wide-angle zoom lens for APS-C cameras, offering a versatile zoom range that provides an equivalent focal range of 17-30mm in 35mm full-frame terms.
The Tamron 11-17mm Sony features 12 elements in 10 groups including one XLD element, two LD elements, and two glass-molded aspherical elements . It has a rounded 7 blade diaphragm which creates an attractive blur to the out-of-focus areas of the image.
The Tamron 11-17mm has an RXD (Rapid eXtra-silent stepping Drive) autofocus motor that delivers very fast and quiet auto-focusing.
It offers an impressively close 0.15m minimum focusing distance and a maximum magnification of 1:4.
This lens has a moisture-resistant construction, a fluorine coating to protect against dust, dirt, and smearing, and a BBAR-G2 coating to suppress flare and ghosting.
The Tamron 11-20mm F2.8 Di III-A RXD lens is priced at around £819 / $829 in the UK and the US, respectively.
Ease of Use
Weighing in at 335g and measuring just over 8.6cm in length, the Tamron 11-20mm F2.8 Di III-A RXD is a very compact and lightweight lens considering the fast maximum aperture and the versatile wide-angle zoom range that it offers.
Note that it does gradually extend further by 1.7cms, though, as you zoom from 20mm to the 11mm focal length.
As with most other recent Tamron lenses that we've reviewed, build quality is fine. The Tamron 11-17mm Sony feels solid enough in your hand, despite its mostly high-grade plastic construction.
It has a metal lens mount and it accepts 67mm filters. It is also weather sealed, adding some peace of mind in more inclement conditions.
The Tamron 11-20mm F2.8 Di III-A RXD has a fairly narrow, ridged focus ring. Manual focusing is only possible by delving into the menu system - there's no dedicated AF/MF switch to toggle between AF and MF on this lens.
The zoom ring is smooth and well-balanced, but the manual focus ring isn't particularly well-damped and and therefore feels light in use.
There are also no hard stops at the ends of the focal range, making it harder to set focus at infinity. Polariser users should be pleased that the 67mm filter thread doesn't rotate on focus.
The Tamron 11-17mm Sony zoom lens utilizes an RXD (Rapid eXtra-silent stepping Drive) autofocus motor for fast and quiet auto-focusing.
It proved to be a very quick performer on the Sony A6600 camera that we tested it with, and we hardly experienced any "hunting", either in good or bad light, with the lens accurately focusing virtually all of the time.
It is also almost completely silent when auto-focusing, making it perfect for movie shooting or for more candid use.
The Tamron 11-20mm F2.8 Di III-A RXD doesn't feature optical image stabilisation, so you'll have to rely on the camera body's own built-in stabilisation system (if it has one).
The Tamron 11-17mm for Sony lens is designed in Japan and made in China.
It's supplied with a good quality plastic petal-shaped lens hood (HA046), but not with a bag or case.
At the 11mm focal length the angle of view is 105° 20'.
At the 20mm focal length the angle of view is 71° 35'.
Chromatic aberrations, typically seen as blue or purple fringes along contrasty edges, were not too apparent in our test shots, only appearing in high contrast areas.
With the lens set to its maximum aperture of f/2.8, there's some light fall-off in the corners, requiring you to stop down by at least 3 f-stops to completely prevent it.
This lens suffers from some very obvious barrel distortion at 11mm and equally obvious pincushion distortion at 20mm.
The Tamron 11-20mm F2.8 Di III-A RXD offers a minimum focusing distance of 0.15m /5.9 in. with a maximum magnification of 1:4, when set to the 11mm focal length, which makes it surprisingly useful for close-ups.
At the 20mm focal length the minimum focusing distance of 0.24m /9.4 in with a maximum magnification of 1:7.6.
Bokeh is a word used for the out-of-focus areas of a photograph, and is usually described in qualitative terms, such as smooth / creamy / harsh etc.
In the 11-20mm F2.8 Di III-A RXD lens, Tamron have employed an iris diaphragm with 7 rounded blades, which has resulted in fairly appealing bokeh.
This lens does suffer from strong onion ring bokeh, though, with the bokeh rings seemingly made up of lots of concentric circles, which may prove off-putting for more demanding users.
In order to show you how sharp the Tamron 11-20mm F2.8 Di III-A RXD lens is, we are providing 100% crops on the following pages.