TAMRON SP 24-70MM F2.8 DI VC USD G2

Like many of Tamron’s recent lenses, this one has a really high-quality look and feel, with performance to match

Tamron’s new G2 (Generation 2) lens feels sturdy, robust and very well engineered, with a metal outer barrel. Like the Sigma, the metal mounting plate is weather sealed, but the Tamron also features weather seals around its other joints and switches. The switches for AF/MF and VC (Vibration Compensation) on/off are rather larger, and easier to operate when wearing gloves. The Tamron also adds a zoom lock switch, although we didn’t experience any problems with zoom creep.

In our review samples, the Tamron’s zoom ring operated a little more freely than the Sigma’s but slightly less smoothly. The direction of rotation for zooming is reversed, compared with the Sigma, more akin to Nikon rather than Canon zoom lenses. Both lenses are available in Canon and Nikon mounting options, while the Sigma is also available in Sigma’s own proprietary mount. The lenses are also compatible with the respective manufacturer’s optional USB consoles for applying customisation and firmware updates.

Autofocus is very quick and extremely quiet in operation, based on a new version of Tamron’s ring-type ultrasonic system. The VC stabiliser is similarly impressive, delivering a five-stop benefit in our tests beating the Sigma’s stabiliser by a full stop.

As with the Sigma, the optical path is complex, this time including two XR (Extra Refractive Index), three LD (Low Dispersion), three GM (Glass-Molded aspherical) and one hybrid aspherical element. Nano-structure coatings as well as conventional coatings are applied and, in our tests, the Tamron edged ahead of the Sigma for minimising ghosting and flare.

As with the Sigma lens, the front element has a wide diameter and the filter attachment thread is typically large for a 24-70mm f2.8 lens, at 82mm. Vignetting is a little more noticeable than from the Sigma when shooting wide open, but largely disappears when stopping down to f4. Again, bokeh is very soft and appealing, both wide open and at slightly narrower apertures, with a similarly well-rounded nine-blade diaphragm.

Another similarity to the Sigma lens is that the aperture is electro-magnetically controlled, in both the Canon and Nikon mount options. An upside is that exposure values tend to be more accurate and consistent during sequences of rapid, continuous shooting. Nikon was relatively late to adopt this method, rather than a mechanical lever, making both the Sigma and Tamron incompatible with some older Nikon APS-C format SLRs. However, there are no incompatibility problems with any of Nikon’s full-frame cameras.

Both lenses deliver excellent contrast and impressive sharpness when shooting wide open. The Tamron is marginally sharper in the 24-35mm section of the zoom range, whereas the Sigma is a little sharper at 50-70mm focal lengths. Colour fringing is even more absent in the Tamron lens than in the Sigma, right into the extreme corners of the image frame, and distortions are similarly well controlled throughout the zoom range.

When it comes to little extras, both lenses are supplied with a petal-shaped hood, although the Tamron’s has a release button so that it locks in place. The Sigma comes complete with a padded soft case, whereas the Tamron is only supplied with a pouch.