Perhaps it is a sign that the Sony mirrorless system has come of age when third party manufacturers start to make lenses to compete with the marque alternatives. Tamron introduces here the new 17-28mm lens for full-frame Sony FE mount cameras, although it can still be mounted on crop sensor bodies if desired. In that case, the “35mm equivalent” field of view becomes similar to a 25.5-42mm. There are already some superb lenses available for Sony FE mount, so it will be very interesting to see how the new Tamron stacks up in terms of both handling and performance. Armed with the 24MP full-frame Sony A7 III, let's find out.

One image can change us.

A picture, a moment can change the way we feel. Change how we see ourselves. Change our understanding and change the rules. Provoke and change history.

MPB puts photo and video kit into more hands, more sustainably. Every month, visual storytellers sell more than 20,000 cameras and lenses to MPB. Choose used and get affordable access to kit that doesn’t cost the earth. Sell the kit you’re not using to MPB. Trade in for the kit you need to create. Buy used, spend less and get more. Buy. Sell. Trade. Create.

Tamron 17-28mm f/2.8 Di III RXD Handling and Features

One fair criticism of Sony's A7 series might be that, despite a small camera body, some of the lenses are every bit as large and heavy as those intended for full-frame DSLRs. This new lens bucks the trend as it is nice and compact, weighing in at a modest 420g. There is extensive use of high-quality plastics and the overall impression is of a very well made lens. It balances well with the camera body and the whole package is compact and fits the hands very comfortably indeed.

Our tour of the lens starts with the small petal-shaped lens hood. This reminds us that we have here an ultra-wide and there is little scope for a deeper hood. The bayonet fit is secure. Within this is a standard 67mm filter thread; usefully this is the same size as Tamron's matching 28-75mm, suggesting that we have a good pair of lenses that will work well together.

The zoom ring is fairly stiff but smooth and is clearly marked in 17, 20, 24 and 28mm focal lengths. Behind this is the manual focus ring, the setting of which is controlled from within the camera menus. The options are manual focus, a dumb ring in AF mode or an active ring in AF mode, where the focus can be tweaked manually. In Sony terms, this last option is designated DMF, or Direct Manual Focus.

Focusing is down to 0.19m (7.5 inches) at the 17mm end and 0.26m (10.2 inches) at the 28mm end. Measurement is from the subject to the sensor plane, not the front element. This means there is very little space for the subject and lighting at the wide-angle end in particular. Maximum magnification is 1:5.2 at 17mm and 1:6 at 28mm. This is not macro, but still usefully close.

Optical construction is 13 elements in 11 groups, including 3 Aspherical, 2 LD (Low Dispersion) and 1 XLD (Extra Low Dispersion). Tamron's BBAR (Broad Band Anti Reflection) multicoating process is used, plus a Fluorine coating on the front element to repel water, oil and dirt. The aperture comprises 9 blades and a rounded opening is ensured at least until two stops down.

Construction is moisture resistant, which is almost a requirement in current lenses and in any event a very useful feature.

Finally, the AF motor delivers very fast and accurate AF. The description RXD refers to Rapid eXtra-silent stepping Drive, but the essential thing is that it works.

Overall, the lens is very pleasant to use, without vices and the only thing that might have been useful beyond that is an AF/MF switch on the lens itself. As it is, we have to delve into the camera menus to switch; hardly the most convenient method.