Canon Zoom Lens EF 24-85 mm f/3.5-4.5 USM Test Results

Canon Zoom Lens EF 24-85 mm f/3.5-4.5 USM

Aperture Range [f]	3.5-4.5 to 22-32	Closest Focus	0.5m / 1.6 ft.
Dimensions	69.5mm x 73mm / 2.7 in. x 2.9 in.	Magnification Ratio	0.16x / 1:6.3
Weight	380g / 13.4 oz	Filter Size	67mm

This is one of the older Canon zoom lenses that fits on full frame, 24x36mm, cameras. It is very light (plastic body) and small, so it is versatile. It focuses well, and fast.

I've tested this lens on 3 focal lenghts: 24, 40, and 85 mm (links to charts made at various f-stops). To see the charts - dependence of image quality on a distance from the image center in the in full magnification please click on the thumbnails below. The average resolution in hundreds of line widths per picture height (LW/PH) is given below each chart. F/11 was the sharpest setting overall.


Tests at low fs	Tests at f/11

At wide open apertures the lens sharpness is good in the image center, but it falls off significantly with increasing distance from the center (unlike the 24-105mm lens). Not the sharpness, however, but low contrast is the problem.

At f/11, the sharpness and contrast are well improved, even at sides of the frame. Chromatic aberrations at all focal lengths are not bad, but clearly worse than in the 24-105 lens.

Distortions are generally low. However, the chart in the center is 7% larger than the one on the side at 24mm (making the objects in the center unnaturally large), but only 2% difference in extreme diameters on the corner chrt; see variable ellipse shapes throughout the frame. At longer focal lengths the circle sizes are more constant. The worst circle deformattion is on the side at 85mm (4.2% diameter difference in the ellipse), a 4x higher distortion than in the "L" zoom mentioned above.

Users of APS-C - sensor cameras may not see much of a difference in sharpness between the 24-105mm lens described here, except at full aperture and 85mm, however, the distortion and lower contrast should be noticeable. For the full frame cameras users this difference in lenses quality is significant.