Canon EF 24-105mm f/4L IS USM
 

Canon EF 24-105mm f/4L IS USM

This review covers


PAGE 2

» Image Quality «


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» 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

35 mm focal length is the sweet spot of the EF 24-105mm f/4L IS USM where it delivers excellent resolution. At 24 mm and 50 mm the lens's resolution is still good but with longer focal lengths the lens gets softer. The more expensive EF 24-70mm f/2.8L USM has a better resolution for the long focal lengths but at the wide end it cannot compete with this lens's good resolution.

-Test shots

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

Distortion

Again 35 mm of focal length seems to be the sweet spot of the EF 24-105mm f/4L IS USM where it doesn't show any distortion. Longer focal lengths show moderate pincushion distortion but at the wide end of the focal range the situation is really serious. The hefty barrel distortion will easily be noticeable in the final image. I was a little shocked when I first saw the test results because after all this is an L series lens. Don't try to photograph architecture at this focal length with the EF 24-105mm f/4L IS USM because architectural photography often requires perfectly straight lines. Stopping down doesn't help with distortion so using a slightly longer focal length (where the lens is great) or software correction are your only options.

-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

At 70 mm there are only slight color errors whereas all other focal lengths show quite visible fringes. Color errors in focused parts of the image are not affected by stopping-down but switch to f/8 in the test shot box below to make sure you are seeing just them.

-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 EF 24-105mm f/4L IS USM shows only slight color fringes in out-of-focus areas of the image. That's good news as this type of color error is hard to correct in post. If even the slight fringes bother you stop down to f/8 to remove them entirely. Note that the lens performs better in this test than the more expensive EF 24-70mm f/2.8L USM.

The aperture shape of the EF 24-105mm f/4L IS USM is evenly round which makes out-of-focus blur smooth and even. Canon use 8 aperture blades of the circular type to achieve this.

-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




Test shot not available.
Why?

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

If the focal plane is curved (rather than straight like a real plane) it can be difficult to get the corners and the center of the image in perfect focus at once. Of course it's a different story if your subject is curved as well but that would be a rare coincidence. The EF 24-105mm f/4L IS USM unfortunately shows a very pronounced curvature of its focal plane when used at 24 mm focal length with a full frame sensor. Stopping down helps but in my test setup I needed to set the aperture to really high f-stops (like f/11) to get rid of the curvature completely. In real life applications this will depend on your distance to the subject (which influences the in-focus range) and might not be as bad (the test setup shows almost the worst case situation).

Fortunately longer focal lengths do not show any curvature so consider using a slightly longer focal length for shots where a perfectly straight focal plane is important. Note that the EF 24-70mm f/2.8L USM has the same problem at the same focal length.

If you are using the EF 24-105mm f/4L IS USM on an APS-C camera you are in luck as there is no relevant curvature to speak of.

-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

The EF 24-105mm f/4L IS USM has quite intense corner shadows when used at the wide end of the focal range. That is to be expected of a wide angle lens but other lenses like the EF 24-70mm f/2.8L USM express less intense shadows (when compared at the same aperture!). Stopping down reduces (but doesn't remove) the shadows and longer focal lengths show a lot less shadow to start with. If corner shadow bothers you please note that it can be removed with software fairly easy.

-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

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PAGE 1

Handling

PAGE 2

Image Quality

PAGE 3

Conclusion

 

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