Tokina AF 11-16mm f/2.8 AT-X Pro DX (Canon) - Review / Lens Test Report - Analysis
Lens Reviews - Canon EOS (APS-C)
Thursday, 01 May 2008 18:54

Distortion

Surprisingly Tokina managed to keep the level of distortion quite well under control. At 11mm there is still fairly pronounced barrel distortion (2.1%) but this is still comparatively low for such a lens. The problem decreases when zooming out towards the long end - at 14mm the barrel distortion is hardly objectionable anymore (1%) and almost negligible at 16mm (0.5%).

Move the mouse cursor over the focal length text marks below to observe the respective distortion
11mm 14mm 16mm

Vignetting

The vignetting characteristic of the Tokina is pretty good. Unsurprisingly the problem is most pronounced at 11mm @ f/2.8 - 1.2EV corner darkening can be visible in some scenes. However, beyond this setting the problem is well under control for such a lens. At 14mm and 16mm there's only a moderate degree of vignetting at large aperture and from f/4 onwards it's basically negligible in field conditions.

MTF (resolution)

The resolution figures of the Tokina are highly impressive and the best that we've seen in this class (within the Canon scope). The lens did not show a single significant weakness throughout the range. The center resolution is excellent, even outstanding towards the long end, and the borders are easily on a very good level at large apertures and excellent around the sweet spot at f/5.6. The extreme corners are not much worse. This may show that a short zoom range can be actually very desirable when it comes to quality.

The field curvature is fairly moderate and not objectionable.

Below is a simplified summary of the formal findings. The chart shows line widths per picture height (LW/PH) which can be taken as a measure for sharpness. If you want to know more about the MTF50 figures you may check out the corresponding Imatest Explanations

Chromatic Aberrations (CAs)

So far things were very rosy but the lens has also a bug - lateral chromatic aberrations - visible as color shadows at harsh contrast transitions. The characteristic is quite uniform across the range with an average pixel width at around 1.5-1.9px at the image borders. This is better compared to its in-house cousin but still not great. A quite typical flaw in many Tokina lenses actually.

Here's a real world sample crop at 200%:

However, don't blow this aspect out-of-proportions - lateral CAs can be fairly easily corrected via various tools such as the Adobe Photoshop RAW converter (ACR).




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