All-round zoom: Canon EF 24-105mm f/3.5-5.6 IS STM

Owners of a full-frame Canon camera who were looking for a standard zoom lens with a limited budget did not have it easy until recently. The obvious standard zoom was of course the 24-105 mm f4L IS USM. But for those for whom that was a bit too expensive, Canon has filled the gap with a new zoom lens, the EF 24-105 mm f/3.5-5.6 IS STM. The zoom range, from 24mm wide-angle to 105mm telephoto, is very popular. From landscape to portrait, with this lens you can tackle a lot of subjects. The lens also has modern image stabilization that is much better than the stabilization of the 28-135 mm and an STM motor that is very suitable for video in combination with the Dual Pixel AF of, for example, the EOS 6D Mark II.

 BUILD

The Canon EF 24-105 mm f/3.5-5.6 IS STM is a relatively light lens. At 525 grams, it is 260 grams lighter than the 24-105 mm f/4L IS USM II. That is not due to the number of lens elements. That is the same for both. The construction is different. For the 24-105 mm f/3.5-5.6 IS STM, a lot of plastic is used, and the lens is not extra-well protected against moisture. The lens is well put together, with little play and smooth zoom and focus rings. The aperture consists of 7 blades. That produces slightly less round bokeh balls than when you have a nine-bladed aperture. It is an odd number, so that you get stars with 14 points if you have small, bright light sources in frame with a small aperture. The lens has switches for autofocus/manual focus and for image stabilization, but no window that indicates the set focus distance.

autofocus

Canon also uses Dual Pixel AF in full-frame cameras. Thanks to this technology, the cameras have phase detection autofocus on the sensor. The advantage is that you can focus quickly and precisely in live view. You have the most benefit from this technique with lenses with STM drive. On APS-C cameras with Dual Pixel AF, we have noticed that with STM lenses you can very nicely shift the focus from one point to another by simply touching another spot on the screen. The focus then slides smoothly without searching for the next focus point. That’s why it’s strange that the 24-105 mm f/3.5-5.6 IS STM was only the second lens for full-frame with STM. The 40mm f/2.8 pancake was the first. For taking pictures, STM is a bit slower than USM, but the difference is not great. The 24-105 mm f/3.5-5.6 IS STM is quick to focus in practice. The STM engine is a fraction quieter than the USM motor, and the accuracy turned out to be higher during our laboratory tests than with the 24-105 mm with USM motor. The biggest trump card of this lens is its ability to follow subjects almost perfectly during filming in Movie Servo AF, thanks to that STM motor. Those who want to film a lot do well to put this lens high on their wish lists for that reason alone.

VIGNETTING, FLARE AND DISTORTION

The image quality of the 24-105mm f/3.5-5.6 IS STM is pretty good, but not perfect. That also applies for actually all other 24-105mm lenses. The sharpness in the center is generally good, with a gradient towards the corners at full aperture. The lens scores better in the wide-angle mode than in the telephoto mode. What you can experience in practice is that the lens suffers from image field curvature. The focal plane is therefore not flat, but a bit convex. If you focus on a flat surface in the middle, the corners will blur out considerably. You can also see that when you focus on subjects that are very close. You will then get a sharp hotspot with a blurry circle around it, unless your subject happens to nicely follow the focal plane. The 24-105 mm f/3.5-5.6 IS STM also has some chromatic aberration, and you can see that in telephoto even more than in the wide-angle mode. Distortion is also present, with clearly perceptible barrel-shaped distortion in the wide-angle mode that runs, through neutral, to clearly pincushion-shaped somewhere between 35 and 50mm. In the wide-angle mode, a good deal of vignetting is also visible at 24 and 28 mm, as well as at 105 mm at full aperture. Of course, lens corrections, both in the camera and in post-editing, can eliminate vignetting, distortion and a large part of the aberrations, and that makes a huge difference. In practice, this lens delivers beautifully sharp images that are not inferior to those from the more expensive L lenses.

IMAGE STABILIZATION

Image stabilization – between the image stabilization of the 28-135 mm and this 24-105 mm f/3.5-5.6 IS STM – has undergone more than ten years’ development, and that is clearly noticeable. The stabilization is good for a four-stop difference. It works nice and silently, and that is an extra bonus when filming. There are only two positions on the slider on the lens for image stabilization: On and Off. Fortunately, this lens itself notices when it is on a tripod and when you are following a subject with it. Then the stabilization only works in one direction and does not work against the panning.

CONCLUSION: REVIEW Canon EF 24-105mm f/3.5-5.6 IS STM

PROS

• Great/versatile zoom range
• Image stabilization
• STM motor for video
• Light
• Price

CONS

• Not dust- and moisture-proof
• Light construction (compared to 24-105mm L versions)