Centre resolution is very good but corner sharpness is disappointing....
Optically, the lens contains eleven elements in six groups, and this includes one aspherical lens. Minimum focus distance is 28cm, while minimum aperture goes to f/22 at the wide end and f/32 at the telephoto end.
The Canon lens is not exactly built to a professional spec, and its plastic construction keeps both the weight and the price down. In use, the body feels clunky, and as the zoom is rotated it’s slightly stiff as the extremities of the focal lengths are reached. This clunky aspect is heightened by the focus action. The motor is fairly loud and ‘whirry’, though focusing is relatively quick and accurate.
The lens mount is also plastic, with a rubber O-ring to maintain light tightness and to provide some protection to the mount and camera body.
Canon sensors tend to produce a softer, lower-contrast image than other cameras, so we need to take that into account. However, this lens is softer in terms of focus than some of the other lenses in this category. Centre resolution is very good but corner sharpness is disappointing and reduces the average, while chromatic aberration is poor. To add insult to injury, the lens also suffers from the higher distortion than some of the other lenses in this category.