Tokina AT-X 12-28mm f/4 Pro DX Lens Review

Tokina AT-X 12-28mm f/4 Pro DX Performance

At 12mm, sharpness in the centre of the frame is already outstanding at maximum aperture, although clarity towards the edges of the frame falls behind somewhat. The performance towards the edges of the frame improves rapidly as the lens is stopped down, with peak sharpness across the frame being achieved at f/8 for this focal length.

Performance is similar in the centre of the frame at 20mm, and clarity towards the edges of the frame is improved at maximum aperture. As is the case at 12mm, peak sharpness across the frame is achieved at f/8 for this focal length.

Performance at 28mm is consistent with other focal lengths. Sharpness in the centre at maximum aperture remains excellent and clarity towards the edges of the frame is good. Stopping down to f/8 results in excellent sharpness across the frame at this focal length.

Resolution @ 12mm

Resolution @ 20mm

Resolution @ 28mm

How to read our charts The blue column represents readings from the centre of the picture frame at the various apertures and the green is from the edges. Averaging them out gives the red weighted column. The scale on the left side is an indication of actual image resolution. The taller the column, the better the lens performance. Simple. For this review, the lens was tested on a Nikon D300 using Imatest.

Chromatic aberrations are well controlled for an ultrawide lens throughout the zoom range, remaining well under three quarters of a pixel width towards the edges of the frame. This low level should pose few issues, even in big enlargements, or harsh crops from the edges of the frame.

Chromatic aberration @ 12mm

Chromatic aberration @ 20mm

Chromatic aberration @ 28mm

How to read our charts Chromatic aberration is the lens' inability to focus on the sensor or film all colours of visible light at the same point. Severe chromatic aberration gives a noticeable fringing or a halo effect around sharp edges within the picture. It can be cured in software. Apochromatic lenses have special lens elements (aspheric, extra-low dispersion etc) to minimize the problem, hence they usually cost more. For this review, the lens was tested on a Nikon D300 using Imatest.

Falloff of illumination towards the corners of the frame is stronger at 12mm than 28mm. At 12mm the corners are 1.42 stops darker than the image centre at f/4, and this drops to the corners only being 0.6 stops darker at 28mm and f/4. Visually uniform illumination is achieved by f/8 at 12mm and by f/5.6 at 28mm.

Distortion is reasonably controlled for an ultra wide zoom lens. At 12mm 4.4% barrel distortion is present, which is reduced to 0.04% barrel distortion at 28mm. The distortion pattern is uniform across the frame, which should make corrections in image editing software easy to apply if straight lines are paramount.

A petal-shaped hood is supplied with the lens, which does a decent job of shading the front element from extraneous light. Contrast is good, even when shooting into the light and only a little flare can be seen in extreme lighting conditions.

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