1. Introduction 2. Design and Operation 3. Test results (APS-C) 4. Test results (Full frame) 5. Image quality 6. Conclusion & samples

Design

The SP 24-70mm F/2.8 Di VC USD looks much like other recent Tamron lenses, with a utilitarian matt black plastic barrel, and a gold band beside the focus ring as the closest to any sort of design flourish. But while the company's consumer-grade lenses tend to be somewhat lightweight in construction, the 24-70mm is anything but, and instead feels reassuringly well put together. The barrel may be plastic rather than metal, but the standard of fit and finish is high, as you'd hope for the price. There's a rubber seal around the mount to help protect from water ingress.

Unusually for this class of lens the zoom ring is placed at the front; on other manufacturers' 24-70mm designs it tends to be positioned towards the rear of the barrel, closer to the centre of gravity of the camera/lens combination. The slim manual focus ring is located centrally on the barrel, with a basic distance scale behind it. Two switches on the left side of the lens turn autofocus and image stabilization on and off, and another switch on the zoom ring locks it at the 24mm position for transport.

Both the zoom and focus rings operate pretty smoothly, but the zoom is relatively stiff. Likewise the AF and VC switches require a little more force than usual to move, partially due to their rather flat profiles which don't provide much purchase. Overall this means that the lens handles slightly less well than its competitors, but we'd consider this an inconvenience rather than a deal-breaker.

Compared to Canon EF 24-70mm F2.8L II USM lens

Left - Tamron SP 24-70mm D/2.8 Di VC USD    Right - Canon EF 24-70mm F2.8L II USM

Here's the 24-70mm F2.8 VC alongside the lens that was announced a day later: the Canon EF 24-70mm f/2.8L II USM. The two are remarkably similar in terms of size and weight; the Tamron is fractionally shorter and heavier, but in practical use they feel essentially the same. The difference in control positioning is clear here, with the Tamron's zoom ring in the same location as the Canon's focus ring.

The table below compares the Tamron's key specifications with all of its main competitors. The Nikon and Sony lenses are notably heavier than the other three, but are narrower in diameter and use smaller 77mm filters. The Nikon lens is the longest of the bunch, while the Sigma is the shortest. It's important to note that the Sony lens doesn't need optical stabilization, because the company's Alpha mount cameras all use in-body sensor-shift image stabilization.

Click here for a detailed specification comparison between current 24-70mm F2.8 lenses from Canon, Nikon, Sigma, Sony and Tamron

On the camera

The 24-70mm is a fairly sizeable beast, and as usual handles best on bodies with a decent-sized handgrip such as the EOS 6D shown left. On the smaller entry-level bodies such as the EOS 650D it becomes more a case of holding the body by the lens than vice versa. The front-mounted position of the zoom ring forces you to cradle the lens with your left hand further forward than usual, which feels a little less natural than lenses with a rear-mounted zoom ring.

Another small criticism is that we find the zoom lock switch to be a little awkwardly-placed if you find yourself suddenly needing to unlock the lens to grab a shot. But this also means that you're unlikely to lock the zoom accidentally; of course it won't matter at all if you choose not to lock the lens when putting it into your bag.

Autofocus

The 24-70mm uses a ring-type ultrasonic focus motor, of essentially the same kind as used in all the other lenses of its type. It's pretty quick and responsive, although in side-by-side testing on the same camera bodies it's clearly not quite as lightning-fast as the Canon equivalent. We've seen no obvious systematic problems with focus accuracy on any of the cameras we've used for testing, ranging from the entry-level EOS 650D, through the enthusiast-orientated EOS 60D, to the semi-pro EOS 6D.

Switch from the optical viewfinder to live view, though, and the story changes. Focusing slows down considerably, although the exact speed will be highly dependent on the camera used. It's still pretty quiet, but if you refocus during movie recording, the clicking of the AF motor as it fine-tunes focus might be audible on your soundtrack in quieter conditions.

Lens body elements

	The 24-70mm is available in Canon, Nikon and Sony mounts; our review sample was the Canon version. If you look closely at this view you can see the rubber seal that surrounds the mount, and helps protect against water penetrating the join between camera and lens. (It's more obvious if you click-through to the larger version.)
	The filter thread is 82mm, larger than the 77mm of the Nikon and Sony equivalents, but the same size as its Canon and Sigma counterparts. Due to the lens's internal focus design, the filter thread doesn't rotate on focusing. This means filters such as polarizers and neutral density gradients are much easier to use.
	The zoom ring rotates 70 degrees clockwise from wideangle to telephoto - the same direction as Nikon and Sony lenses, but opposite to Canon. It's marked at the 24, 35, 50 and 70mm positions. The ridged rubber grip is 33mm wide, and rotates with a smooth but rather stiff action.
	The slim focus ring has a 11mm-wide ridged rubber grip. It rotates 90 degrees anti-clockwise from infinity to 0.38m - again the same as Nikon lenses, but opposite to Canon and Sony. Its action is nice and smooth, and it doesn't rotate on autofocus. The lens has a basic distance scale, with markings in metres and feet, but no depth-of-field indicators or IR focus index.
	Two switches on the side of the of the lens barrel control the autofocus and image stabilization. They're quite stiff and have relatively flat profiles, which makes them a little awkward to set. They're also identical in design, so can't be distinguished by touch alone. As usual for a lens with a ring-type ultrasonic motor, you can manually tweak the focus in AF mode.
	There's a switch on the other side of the barrel that locks the zoom in its fully retracted position (i.e. 24mm).
	The bayonet-mount petal-type hood is provided as standard, and clicks positively into place on the front of the lens. The hood is made from thick plastic, and ribbed mouldings on the inside minimize the reflection of stray light into the lens.
	The hood reverses neatly for storage, and the lens comes supplied with a chunky, easy-to-grip centre-pinch front cap.

Reported aperture vs focal length

The 24-70mm VC offers an aperture range from F2.8 - F22 at all focal lengths.

1. Introduction 2. Design and Operation 3. Test results (APS-C) 4. Test results (Full frame) 5. Image quality 6. Conclusion & samples

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Tamron SP 24-70mm f/2.8 Di VC USD Lens (Canon EF Mount)●	$1,299.00	Buy on GearShop
Tamron SP 24-70mm f/2.8 Di VC USD Lens (Nikon F Mount)●	$1,299.00	Buy on GearShop
Tamron SP 24-70mm f/2.8 Di VC USD Lens (Sony A Mount)●	$1,299.00	Buy on GearShop