The front diameter for both lenses is 77 mm. Something you need to keep in mind when you're buying filters.

The lenses have different coating, as evident by the different colours.

There's little difference in size between the two lenses. The Canon lens (right) is a bit narrower in the middle and in the back. This is partly due to the USM (ultrasonic motor) which takes up less space than the classic mm (micromotor).

Bayonet mounts differ a bit, too. The Tokina (left) has Canon EF mount, compatible with every Canon EOS camera, while the Canon lens uses a modified EF-S mount, which can only be used on certain cameras (300D, 10D, 20D, 350D, 30D, 400D). The Canon lens also has a more protruding back end, which reaches deeper into the camera, permitting a closer distance between the sensor and the rear element.

This picture clearly shows the difference between the normal EF mount (left) and the EF-S mount (right). EF-S has an additional flange above the metal part.

For switching between manual and autofocus, the Canon employs the familiar button on the upper left side of the lens. Tokina, however, requires that the focusing ring is pushed towards the camera for manual focusing and away from the camera for auto focusing. In spite of this difference, it's never difficult to know which mode the lens is in.

Canon EF-S 10-22 mm @ 10 mm. Despite only 2 mm difference in focal length, the Canon has a noticeably wider field of view.

Tokina DX 12-24 mm @ 12 mm. The difference between the lenses is apparent in the width of the scene they capture. This is difference enough to put them into separate classes.. Looking at the upper corners of both pictures, some vignetting is noticeable. It is very similar in both lenses, and the difference between the left and the right side is mostly due to different incident light angles. Considering their extreme wide angle, vignetting is very well controlled.

Canon EF-S 10-22 @ 10 mm, f/4, 1/1250 s

Tokina DX 12-24 @ 12 mm, f/4, 1/1600 s In the centre, the image appears better, due partly to the narrower viewing angle and high magnification. In this case, Tokina has the advantage. However, at f/4, the Canon has a significant advantage at the edges. One measure of lens quality is also how consistent their image quality is from the centre to the edge.

Canon EF-S 10-22 @ 10 mm, f/8, 1/320 s

Tokina DX 12-24 @ 12 mm, f/8, 1/400 s At f/8, the Tokina really shines. Both in centre and on the edges, the image quality is a bit better than Canon's. However, the Tokina has slightly more chromatic aberration at the edge (left).

Canon EF-S 10-22 @ 10 mm, f/16, 1/80 s

Tokina DX 12-24 @ 12 mm, f/16, 1/60 s Both images are very comparable. At f/8 and higher, the Tokina starts to lose contrast, and the image starts losing sharpness.

Canon EF-S 10-22 mm @ 10 mm. Image samples at different apertures (from left) 3.5, 5.6, 8, 11, 16. The lens has very consistent image quality at all apertures. The only two that deviate slightly are the maximum, 3.5, and the minimum, 22.

Tokina DX 12-24 mm @ 12 mm. Image samples at different apertures (from left) 4, 5.6, 8, 11, 16. This is where the differences between the lenses and their prices become noticeable. At f/4, the Tokina is very soft. At f/8, image quality peaks, and then starts decreasing as we approach f/16.

Canon EF-S 10-22 mm @ 22 mm. At this focal length, vignetting is pronounced.

Tokina DX 12-24 mm @ 24 mm. Even at normal wide angle, 22 and 24 mm respectively, the difference is still noticeable.

Canon EF-S 10-22 @ 22 mm, f/1000, 1/4 s

Because the lighting was different and because there was more sky in the picture, the image is 0.6 EV underexposed compared to Tokina. Therefore, some details are recorded differently.

Tokina DX 12-24 @ 24 mm, f/4, 1/1600 s

To me, the Canon captured the clock better, while the Tokina has the edge in the windows to the left. However, this is more due to the different exposure (1/1000 compared to 1/1600) than to different optics. In this shot, the Tokina shows that it's much more balanced at 24 mm than it is at 12 mm.

Canon EF-S 10-22 @ 22 mm, 1/400 s, f/8

Tokina DX 12-24 @ 24 mm, f/8, 1/320 s

Again, the difference is due to different exposure. Digital capture differs markedly from analogue capture. A relatively minute difference in exposure results in major difference in tonality, contrast and sharpness.

Canon EF-S 10-22 @ 22 mm, 1/100 s, f/16

Tokina DX 12-24 @ 24 mm, f/16, 1/80 s

At this focal length, the Tokina is every bit as good as the Canon. At half the price.

Canon EF-S 10-22 mm @ 22 mm. Image quality at different apertures, from the left: 4, 5.6, 8, 11, 16. The Canon lens has a wider field of view, making the camera meter more of the sky. Therefore, these images have an approximately 0.5 EV exposure difference compared to the Tokina images. This series also shows that there were metering differences between various apertures.

Tokina DX 12-24 mm @ 24 mm. Image samples at different apertures (from left) 4, 5.6, 8, 11, 16. No major differences in image quality. At longer focal lengths, the Tokina corrects many shortcomings that were evident at short focal lengths. The image is quite consistent at different apertures.  Because less sky was used for the metering, there's an exposure difference of about 0.5 EV, making Tokina's details brighter.

Canon @ 22 mm (left), Tokina @ 24 mm (right). At wide angle, the 2 mm focal length difference is very noticeable.

Canon EF-S 10-22 @ 22 mm, 1/125 s, f/11. Sharpness and contrast are a bit better.

Tokina DX 12-24 @ 24 mm, f/11, 1/160 s

At the focus point, the image quality is very good. The more distant parts of the scene (still within the depth of field), however, show decreased image quality when compared to Canon.

Canon EF-S 10-22 @ 22 mm, 1/125 s, f/11

Canon's image still has sufficient contrast with minimal chromatic aberration.

Tokina DX 12-24 @ 24 mm, f/11, 1/160 s

The image is not as sharp, and chromatic aberration is more pronounced.

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This image was taken in identical conditions. EOS 20D, both at 12 mm, ISO 200, 1/200 s, f/4.5.

Canon left, Tokina right. At 100%, the Tokina images look better due to higher contrast. On the whole, however, Canon's tonality is better. More distinct tonal values can be observed. Unfortunately, they both lack sharpness. However, this is not unusual for wideangle lenses.

Canon left, Tokina right. 100% crop. In this part, the Canon is more contrasty and cooler. Chromatic aberration is more pronounced as well, with blueish fringing in Canon and red fringing in Tokina. However, in both images, image quality differs from one detail to another. Sometimes Tokina is better and sometimes Canon is better.

The whole image, with 100% crops below. Canon left, Tokina right.

EOS 20D, both at 12 mm, 1/320 s, f/8.

Unlike the images on page 2, these images were taken in cloudy weather, in very diffuse lighting. In such lighting, there are no differences between the two.

Canon EF-S 10-22 mm @ 12 mm, f/3.5.

This is as good as bokeh tests get in ultra wide angle. The foreground is in focus, while the background is unsharp.

Tokina DX 12-24 mm, 12 mm, f/4.

No differences in sharpness and tonality. However, there is a difference in background blur. Apparently, in Japan, bokeh is as important as sharpness. Looking at the above picture, Canon's bokeh at f/3.5 seems nicer. Tokina's bokeh, on the other hand, is too contrasty.

Canon EF-S 10-22 mm @ 12 mm, f/8.

Only the foreground is sharp, and that's only 10-30 cm from the lens. Background is not within the depth of field. Again, Canon's background is smoother.

Tokina DX 12-24 mm, 12 mm, f/8.

Even though the Tokina seems to capture the background better, producing more depth of field, the difference is mainly due to contrast. There's no softness to the background blur. If you want proof that that's not sharpness, look at the letters in background. They're not sharp, they're just contrasty. So this is bokeh, the poetic blur, another factor in lens quality. However, in wideangle lenses, it's far less important than in telephoto lenses, especially portrait lenses.

Canon EF-S 10-22 mm @ 12 mm, f/16.

The only noticeable difference between the two shots at f/16 is that the clouds drifted a bit, changing the lighting and the window reflections.

Tokina DX 12-24 mm, 12 mm, f/16.

At f/16, the depth of field is so large that even in the background building, no major differences are noticeable. Since the lighting changed a bit, the two images are exposed slightly differently. In both cases, shutter time was 1/50 s.

Canon EF-S 10-22 mm @ 12 mm, f/3.5.

Tokina DX 12-24 mm, 12 mm, f/4.

At nearby subjects, the Tokina has excellent sharpness when wide open. The sign in the middle and the stars to the left are sharper than those captured by Canon. Tokina rendered the shadow under the black border differently. Canon rendered is as gray, while Tokina makes it slightly yellowish. Barrel distortion is also apparent on the license plate.

Canon EF-S 10-22 mm @ 12 mm, f/8.

Tokina DX 12-24 mm, 12 mm, f/8.

Image quality at this aperture is very similar to image quality wide open. This is not the kind of scene that could be used to judge depth of field or bokeh. This all means that a stopped down aperture increases image quality. However, in nearby subjects, this is not noticeable.

Canon EF-S 10-22 mm @ 12 mm, f/16.

The results regarding the shadow and the barrel distortion are still very similar. However, at f/16, the Canon lens is a bit sharper at the edges and in the centre.

Tokina DX 12-24 mm, 12 mm, f/16.

In all Tokina samples, it is obvious that it functions best at medium apertures. But here's the catch. You're viewing 100% crops from 8 MP sensors. That's not how you normally view a photograph. There are differences, certainly. It's upon you to decide how much they mean to you. We all know we're all very critical when it comes to evaluating such equipment. But then, there's that other factor that completely shifts the focus. Your bank account.