Introduction

Canon EF 24-70mm f/2.8L USM, first announced at Photokina 2002, replaced an earlier pro-grade standard zoom model - EF 28-70mm f/2.8L USM, which was one of the favorites among professionals and amateurs alike. At the time of this review, EF 24-70mm f/2.8L USM is the fastest L class lens in Canon's arsenal of standard zoom lenses. Priced at ~US$1,000 (as of November 2007), the lens is certainly not cheap, but is still affordable to serious amateurs (and obviously professionals).

The optical construction of the lens consists of 16 elements in 13 groups, including two aspherical and a single ultra-low dispersion (UD) glass elements. The build quality of the lens is very good and like with all of Canon's L class lenses, the outer barrel is made of hardened plastic, which gives the lens pretty solid look and feel. The focusing and zoom rings are fully rubberized and are very smooth. There's no wobbling inside or out, despite all the moving parts - the inner cams of the lens actually extend during zooming towards the wide end of the zoom range. At 950g (2.1lb) and 83 x 113mm (3.3 x 4.9in), Canon EF 24-70mm f/2.8L USM is bulkier and heavier then many other standard zoom alternatives.

The lens sports fast and silent ring-type USM AF as well as full-time manual focusing system, which is controlled by an AF/MF switch on the side of the barrel. Like most modern lenses, Canon EF 24-70mm f/2.8L USM has electronic aperture control, meaning that there's no dedicated aperture ring and all aperture settings have to be set from the camera. The minimum focusing distance is 38cm (1.25ft) and the minimum aperture is f/22. The lens accepts 77mm filter thread and since the front element of the lens does not rotate, can accept circular polarizers.

 

Image

 

The lens carries EF designation, meaning it is designed for full frame cameras, so on an APS-C type body with 1.6x crop factor, the field of view of the lens resembles that of a 38-112mm lens on a full-frame body. The factory box includes Canon EF 24-70mm f/2.8L USM lens, front and rear caps, EW-83F lens hood, LP1219 soft lens case, manual and registration card. The lens is compatible with Canon's Gelatin Filter Holder Adapters III and IV as well as EF 12 II and EF 25 II extension tubes.

 

Summary
Lens Composition 16 elements in 13 groups
Angular Field 74-29 degrees
Minimum Focus 38cm/1.25ft
Focusing Action AF/MF, USM
f-stop Scale f/4-f/22, camera-controlled
Filter Size 77mm
Lens Hood EW-83F (included)
Weight 950g/2.1lb
Dimensions 83x123mm/3.3x4.9"
Lens Case LP1219 (included)

 

Field Tests

The lens fared quite well in the field - image quality was superb throughout tested aperture range and across the supported zoom range. Visually, border quality was more or less on par with center quality, although both seemed to deteriorate ever slightly towards the longer end of the zoom. Color representation was quite accurate with images showing good to excellent levels of contrast throughout the zoom range.

 

Vignetting @ f/2.8 - full frame vs 1.6x crop (24mm)
Vignetting @ f/2.8 - full frame vs 1.6x crop (24mm)

 

Vignetting @ f/2.8 - full frame vs 1.6x crop (70mm)
Vignetting @ f/2.8 - full frame vs 1.6x crop (70mm)

 

The lens showed minor levels of vignetting on a full frame body with wide open aperture. Vignetting at f/2.8 is persistent throughout the zoom range, but basically disappears once stopped down to f.4 and beyond. The lens fared much better on an APS-C camera, where it shows basically no vignetting throughout the zoom and all aperture levels. Canon EF 24-70mm f/2.8 showed very good control of color fringing as well as held up nicely against flare. The lens also did not show any major distortion throughout the zoom range, which while a positive attribute in any lens should not come as a surprise for a standard zoom lens.

 

ISO 100, 1/2500, f/2.8, 24mm
ISO 100, 1/2500, f/2.8, 24mm
Canon EF 24-70mm f/2.8L USM image gallery...

 

Lab Tests

Please note that MTF50 results for APS-C and Full-Frame cameras are not cross-comparable despite the same normalized [0:1] range used to report results for both types of cameras.

 

Canon APS-C: Canon EF 24-70mm f/2.8L USM showcased very solid performance on an APS-C type camera. Center performance was excellent throughout the zoom range, typically reaching best performance by f/5.6. Border quality was lagging a bit - this is especially noticeable at wider apertures, but even there the shows pretty consistent results. f/5.6-f/8 gives the best results and here here the lens is capable of producing outstanding 16in prints throughout the zoom range. Conclusion? Very decent overall performance for a standard zoom lens.

 

MTF50 (Line Width/Inch on the Print) @ 24mm
MTF50 (Line Width/Inch on the Print) @ 24mm

 

Normalized raw MTF50 @ 24mm
Normalized raw MTF50 @ 24mm

 

MTF50 (Line Width/Inch on the Print) @ 35mm
MTF50 (Line Width/Inch on the Print) @ 35mm

 

Normalized raw MTF50 @ 35mm
Normalized raw MTF50 @ 35mm

 

MTF50 (Line Width/Inch on the Print) @ 50mm
MTF50 (Line Width/Inch on the Print) @ 50mm

 

Normalized raw MTF50 @ 50mm
Normalized raw MTF50 @ 50mm

 

MTF50 (Line Width/Inch on the Print) @ 70mm
MTF50 (Line Width/Inch on the Print) @ 70mm

 

Normalized raw MTF50 @ 70mm
Normalized raw MTF50 @ 70mm

 

Chromatic aberration was quite low on an APS-C camera. CA in the center did not exceed ~0.7px across the aperture and zoom ranges, and averaged ~0.5px in most cases. Border CA was also under control, averaging ~0.8px at wide aperture levels and dropping to even lower levels with stopped down apertures.

 

Image borders @ 24mm (100% crop): f/2.8 vs f/8
Image borders @ 24mm (100% crop): f/2.8 vs f/8

 

Image borders @ 35mm (100% crop): f/2.8 vs f/8
Image borders @ 35mm (100% crop): f/2.8 vs f/8

 

Image borders @ 50mm (100% crop): f/2.8 vs f/8
Image borders @ 50mm (100% crop): f/2.8 vs f/8

 

Image borders @ 70mm (100% crop): f/2.8 vs f/8
Image borders @ 70mm (100% crop): f/2.8 vs f/8

 

Canon FF: The lens continued to perform quite well even on a full frame body. Center performance was outstanding straight from f/2.8 across the entire zoom range. Border quality matched that in the center, with no major fall-offs throughout the zoom range. The lens did not show any weaknesses and performance was surprisingly consistent, which by itself is a major advantage in any lens. Conclusion? The overall image quality is surprisingly good, backing the 'superiority' perception of an L lens.

 

Normalized raw MTF50 @ 24mm
Normalized raw MTF50 @ 24mm

 

Normalized raw MTF50 @ 35mm
Normalized raw MTF50 @ 35mm

 

Normalized raw MTF50 @ 50mm
Normalized raw MTF50 @ 50mm

 

Normalized raw MTF50 @ 70mm
Normalized raw MTF50 @ 70mm

 

CA on a full-frame body was quite low as well, not exceeding ~0.6px in the center and ~0.8px around borders throughout the zoom range and across the aperture settings (averages were even lower, with CA around center averaging ~0.5px and ~0.6px around borders).

 

Image borders @ 24mm (100% crop): f/2.8 vs f/8
Image borders @ 24mm (100% crop): f/2.8 vs f/8

 

Image borders @ 35mm (100% crop): f/2.8 vs f/8
Image borders @ 35mm (100% crop): f/2.8 vs f/8

 

Image borders @ 50mm (100% crop): f/2.8 vs f/8
Image borders @ 50mm (100% crop): f/2.8 vs f/8

 

Image borders @ 70mm (100% crop): f/2.8 vs f/8
Image borders @ 70mm (100% crop): f/2.8 vs f/8

 

Alternatives

Standard zoom category is one of the most popular among lens manufacturers, with Canon alone offering more then a dozen standard zoom lenses. However, while the number of choices is quite wide, the list of quality ones is quite short. Among Canon lenses, take a look at EF 24-105mm f/4L IS USM (review) and EF-S 17-55mm f/2.8 IS USM (review), the latter one suitable only for APS-C type cameras. Outside of the Canon camp, take a look at Tamron's SP AF 17-50mm f/2.8 XR Di II LD ASPH (review) and SP AF 28-75mm f/2.8 XR Di LD ASPH (review). Finally, you might want to examine Sigma's 17-70mm f/2.8 EX DC HSM, assuming you have an APS-C camera that is.

 

Recommendation

Canon EF 24-70mm f/2.8L USM is a pretty solid lens with great overall optical characteristics, solid build quality and low level of artifacts (such as vignetting and chromatic aberration). Unfortunately, like most L lenses, EF 24-70mm f/2.8 is quite expensive (not the most expensive lens standard zoom on the market, but not affordable either). The sheer size and weight of the lens can also be considered as negative by some users. Nevertheless, EF 24-70mm f/2.8L has one of the most practical zoom ranges (when used on a full frame camera that is) and can potentially become your favorite if you're looking for a versatile zoom and are not willing to sacrifice image quality.