Canon EF 24-70mm f/2.8L USM
 

Canon EF 24-70mm f/2.8L USM

This review covers


PAGE 2

» Image Quality «


PAGE 3

» Sample Pictures «

» Conclusion «

» Further Information «


Table of contents

Image Qualityhide all test shotsshow all test shots

Note: the test shots for each of the image quality tests can be compared directly amongst all tested lenses. Within the test box click on "Choose lens to compare with..." to add a lens to the comparison. Then use your mouse to hover over the lens thumbnails. If all those test shots are a little too overwhelming consider clicking on "hide all test shots" above this paragraph.

Sharpness / Resolution

L series lenses come with a certain price tag that sets high expectations. In regard to resolution I have to say that I am a little disappointed of the EF 24-70mm f/2.8L USM. While the longer focal lengths offer some good sharpness the wide end of the focal range is pretty soft. At 24 mm and 35 mm focal length the lens cannot compete with it's lower cost companion the EF 24-105mm f/4L IS USM though at 50 mm (slightly) and at 70 mm (clearly) the EF 24-70mm f/2.8L USM is sharper. But even at the tele end it is a lot softer than the EF 70-200mm f/2.8L IS II USM that it often teams up with.

Remember that sharpness / resolution is only one of the image quality factors and the lens does perform better in others (see below).

-Test shots

Full FrameAPS-C    tested with 5D Mark II
Sharpness / Resolution

Distortion

The EF 24-70mm f/2.8L USM shows some barrel distortion at 24 mm focal length and some pincushion distortion at 70 mm. The wide angle performance is really great for a general purpose standard zoom lens and much better than that of the EF 24-105mm f/4L IS USM but of course some primes and dedicated ultra wide angle zoom lenses are able to show even less distortion at 24 mm. At mediocre focal lengths the EF 24-70mm f/2.8L USM does not show any relevant distortion.

-Test shots

Full FrameAPS-C    tested with 5D Mark II
Distortion
Aperture:
Irrelevant

Crop from top of image (downsized)

Crop from bottom of image (downsized)

Best case: the line between the black and white boxes is completely straight in both test shot crops

Color Errors Transverse Chromatic Aberrations

The EF 24-70mm f/2.8L USM shows quite visible color fringes throughout its focal range with the best performance at 70 mm. The performance is similar to that of the EF 24-105mm f/4L IS USM. Of course the test shots shown are taken from the image corners where this type of color error is worst.

-Test shots

Full FrameAPS-C    tested with 5D Mark II
Color Errors

Crop from lower image border
(in landscape orientation)

Color errors in focused parts of the image (upscaled)

 

Best case: no color fringes

Crop from left image border
(in landscape orientation)

Beauty of blurred image parts Bokeh and Axial CA

The color fringes in out-of-focus areas of the image are noticeable throughout the focal range of the EF 24-70mm f/2.8L USM. Stopping down to f/8 and higher removes them. The aperture blades of this lens are of the circular type and Canon use 8 of them to create a nicely round aperture shape. That's good because it will make out-of-focus areas of the image look more even which most people find pleasing.

-Test shots

Full FrameAPS-C    tested with 5D Mark II
Beauty of blurred image parts

The way blurred parts of the image look depends on several things such as focal length, aperture setting, aperture shape, distance to the background, distance between foreground and background as well as the texture and dynamic range of the background. With so many things to consider it's very difficult to compare different lenses. Moreover the beauty of blurred image parts is also a matter of personal taste.

In general blurred image parts should be as uniformly blurred as possible and ideally not show any artifacts. Out of the above mentioned criteria only the shape of the aperture cannot be influenced by the photographer and thus this test will show you the shape you are dealing with (left test image). To minimize artifacts there should be no bright line around the edge of the aperture shape. To get uniform blur the aperture should be as circular as possible (which depends on the number of aperture blades used and their individual shape). Furthermore there should be no color fringes in out-of-focus areas of the image (middle and right test shots).

Aperture Shape

Number of aperture blades:  8
Type: circular
Best case: circular and evenly bright

Color errors in out-of-focus areas of the image (upscaled)

before focal plane

behind focal plane

Crops from the center of the image
Best case: no color fringes in out-of-focus areas

Curvature of the focal plane Field Curvature

Unfortunately curvature of the focal plane is a real issue with the EF 24-70mm f/2.8L USM - at least when used at 24 mm focal length on a full frame body. You can help it by stopping down but in our test setup I needed really high f-stops like f/11 to remove the curvature. Real life results will vary deping on the in-focus range which changes with the distance to the subject but getting the corners and center of an image in perfect focus at once will be tricky at this focal length. The lens does not express curvature of the focal plane for any of the other focal lengths so instead of stopping down you could also use a slightly longer focal length where straightness of the focal plane is paramount.

The lens's performance in this test is very very similar to that of the EF 24-105mm f/4L IS USM.

Because APS-C sensors only show you an inner crop of a full frame image their image corners are a lot closer to the center than with full frame sensors. Thus curvature is generally less of an issue and with this lens it's not an issue at all on an APS-C body.

-Test shots

Full FrameAPS-C    tested with 5D Mark II
Curvature of the focal plane

Crop from the corner of the image
focused at the image corner

 

Best case:
no difference

Crop from the corner of the image
focused at the image center

Corner Shadow Vignetting

Any lens used at 24 mm focal length will show corner shadows. Part of that is just plain physics and cannot be avoided. Good lenses should however get rid of the shadows once you stop down and the EF 24-70mm f/2.8L USM doesn't quite accomplish that. It does reduce the shadows with higher f-stops but they are always visible (for that focal length). Compare with the EF 24-105mm f/4L IS USM (at the same aperture!) to see that that lens has even darker corner shadows. Longer focal lengths are a lot better but I personally don't worry much about corner shadow anyway as it can be used creatively in an image. If you hate it you can easily remove it with software.

-Test shots

Full FrameAPS-C    tested with 5D Mark II
Corner Shadow

Crops (100%)

Corner

Center

Best case: no difference in brightness

Test shot (downsized)

Corner

Center

Best case: perfectly even brightness

Result-Chart

Best case: no color gradient

EV

0

-1

-2

-3

-4

-5

PAGE 1

Handling

PAGE 2

Image Quality

PAGE 3

Conclusion

 

top