Design

From the moment you pick up the 12-24mm F4, its reassuringly weighty design exudes an impression of quality. Tokina has a reputation for excellent build, and this lens well and truly lives up to it; fit and finish is top of its class, and the controls are silky smooth in operation. As expected at this level, the mount is metal, and the barrel made from high quality plastics over a metal sub-structure. The zooming and focusing mechanisms are fully internal to the lens barrel, and this lack of external movements further reinforces the impression of solidity.

Special mention has to be made of the focus clutch system, which is one of the better implementations of this concept. Simply pull the focus ring towards you to switch to manual focus, and back again to return to autofocus; the clutch engages smoothly each time. Occasionally, however, it does result in a slight change in the focus position, so isn't perfectly reliable if you like to set focus using AF, then lock it by switching to manual.

On the camera

The Tokina 12-24mm F4 is a fairly chunky lens, indeed one of the largest and heaviest in its class. This means that it balances best on larger DSLRs such as the Nikon D300 as shown here; however on smaller cameras it's still perfectly manageable. The zoom ring falls naturally to hand, with the focus ring towards the front of the barrel.

It's worth pointing out that this lens isn't terribly compatible with the on-board flashes found on DSLRs; most of these only cover an angle of view equivalent to using an 18mm lens. At wider angles, the flash will give uneven frame coverage with darkening towards the corners, coupled with shadowing from the lens itself in the lower centre of the frame. This is absolutely normal for a wideangle zoom; if you really want to use this lens with flash you'll need to invest in a suitable external unit.

Autofocus

On the Nikon mount lens used for this review, focus is driven by the screw-drive mechanism from the camera body. This version of the lens therefore won't autofocus on Nikon's entry-level D40 / D40X / D60 bodies, and owners of these cameras will need to buy the revised 'II' version with its built-in AF motor. On the Nikon D300 used for testing, autofocus was fast, decisive and accurate, however this is really more a reflection of the camera body's abilities than anything else.

Lens body elements

	The lens comes in versions for Canon and Nikon DSLRs. Our sample was the original Nikon F mount version, with 'screw-drive' autofocus coupling. Five and a half turns are required to drive the lens from infinity to closest focus. Users of Nikon's entry level DSLR line (D40 / D40X / D60) will need to buy the new 'II' version of this lens to get autofocus.
	The filter thread is 77mm. It does not rotate on autofocusing, which should please filter users. A note of warning though; normal 8mm-thick polarisers will vignette significantly with the lens set to 12mm, so you'll need to use a slim-mount one instead. Click here for an example of this vignetting (upper left quarter of the frame, 12mm F8, standard-type Hoya polariser).
	The large petal-type BH-777 bayonet-mount hood is provided as standard, and fits positively onto the front of the lens. It's made of thick black plastic, and is lined with black felt to minimize reflections of stray light into the lens. A white dot on the outside aids alignment for mounting.
	The broadly-flared design does however mean the hood will take up more than its fair share of space in your bag. It's no less than 10.3cm / 4.1" in diameter.
	The zoom ring is slightly narrow at 14mm, but the action is extremely smooth and precise. It rotates 60 degrees clockwise from 12-24mm; the 'right' way for Nikon owners, but opposite to Canon lenses. Zooming is fully internal, so the lens stays the same length at all focal lengths.
	The 18mm wide focus ring rotates 90 degrees anticlockwise from infinity to 0.3m, again matching Nikon lenses and opposite to Canons. A basic distance scale is marked in feet and meters, and the focus ring travels slightly past the infinity position. The feel of the focus ring is again excellent, silky smooth and highly precise, allowing consistently accurate manual focus.
	Manual focus is engaged by pulling the focus ring towards the camera body. A nice feature of this mechanism is that the focus ring does not rotate during autofocus. Care must be taken, though, because the set distance can change slightly on engaging manual focus (as seen here). This means that using the camera's AF to focus, then switching to manual to lock, doesn't necessarily work perfectly.

Reported aperture vs focal length

The lens allows apertures of F4 to F22 to be selected at all focal lengths.