Review Sigma 24-105 mm f/4 Art (C APS-C)
|With the Art series, Sigma has built a series of lenses that in terms of build and image quality are better than the best lenses from the competition, including the biggest camera brands. This time, we tested the Sigma 24-105 mm Art on a Canon 650D, a camera with an APS-C sensor, for two groups of readers. Most of our readers have an SLR camera with an APS-C sensor. Some of them are considering stepping up to a camera with a full frame sensor and keep that in mind when purchasing their lenses. And there are photographers who use their lenses both on a camera with a full frame sensor and on a camera with an APS-C sensor. For both groups of photographers, the Sigma 24-105 mm f/4 Art is an attractive lens that they will enjoy for a long time.||
Sigma 24-105 mm f/4 DG OS HSM Art @ Canon 650D
|On a camera with an APS-C sensor, a 24-105 mm zoom lens provides a field of view that corresponds to the field of view of a 39-146 mm lens on a camera with a full frame sensor. Thus, this is still a useful walk-around lens for photography, portraits or vacations. The Sigma 24-105 mm Art lens comes with a pouch and a flower-shaped lens hood. It's designed for use on a camera with a full frame sensor.|
The Art series lenses are so solidly built that they compare with the best professional lenses of the major camera manufacturers. If you put the Canon 24-105 mm f/4 L next to the Sigma 24-105 mm, the Sigma looks more modern. You also notice that the Sigma lenses are more professional, heavier. The Sigma lenses do not suffer from "creeping", shifting of the zoom if the lens hangs vertically. Our Canon test model definitely suffered from that. Both the zoom ring and the focus ring of the Sigma 24-105 mm Art are perfect muted. The Sigma is heavier, larger and has a larger filter size than the Canon.
|The lens is equipped with two switches: image stabilization on/off and auto focus/manual focus. These switches have a – hand-painted – white background, allowing you to better see which setting the switch is in.
The HSM drive of the auto focus is fast and can be overruled manually if you want to adjust the focus point. We did not encounter front focus or back focus during this test. The Sigma 24-105 Art and the Canon 24-105 mm L are evenly matched on speed, accuracy and reproducibility of the AF.
We tested the image stabilization (OS) at a focal length of 50 mm. The image stabilization turned out to be not only very, very silent, but also effective. The Imatest measurements showed that a hand-held shot at a shutter speed of 1/200 was slightly less sharp than a picture made at a shutter speed of 1/25 second using the built-in image stabilization. That is a real gain of 3 stops, and that's good.
The chart on the right shows the results from our Imatest measurements of in-camera jpg files. The sharpness in the corners at all focal lengths starting at full aperture is just as high as the sharpness in the center. At the longest focal lengths, we measured, relatively speaking, the lowest resolution, but the center resolution was still over 2000 lines per picture height. All very good.
Across the board, the Sigma 24-105 mm on an APS-C – as in our previous test on a camera with a full frame sensor – rated similar, or just a little bit better, than the Canon 24-105 mm that we previously tested. In our review of results at individual focal lengths you can compare the sharpness of the Sigma 24-105 mm with that of the Canon 24-105 mm. Below you'll see a partial enlargement of a test shot made at the longest focal length and maximum aperture. In such situations you also on a camera with a relatively small APS-C sensor get an attractive bokeh.
Click (2x) with your mouse on the image below.
|On a camera with an APS-C sensor, you will rarely suffer from visible vignetting. We start from "What You see is What You get" and use thereafter 1 scale for assessing the vignetting of all lenses, regardless of the sensor size. All lenses tested on a full frame sensor camera have relatively big problems with vignetting. This also applies to the Sigma 24-105 mm Art.
This vignetting disappears like snow in the sun when you look at the results obtained with a Canon 650D test camera.
As with many of this type, sometimes you see (especially at the shortest focal lengths) visible barrel distortion. That is fortunately easy to correct with software, for example with lens correction profiles in Photoshop or Lightroom.
Bokeh Sigma 24-105 mm f/4 Art
Many photographers who use a camera with a full frame sensor find the bokeh important. The aperture of the Sigma 24-105 mm Art is composed of 9 rounded blades, which yields a smooth background blur, even on a camera with an APS-C sensor. See, for example, the larger version of the above test shot. The bokeh is also illustrated by following shot, which we made prior to the test to discern any front or back focus and any colour bokeh. None were present.
Flaring Sigma 24-105 mm f/4 Art
|Like the other recent lenses from Sigma, this lens is well protected against flaring. We didn't encounter ghosts in our test shots made at maximum aperture and different focal lengths. Even if you are shooting straight into the sun, the flare zone is limited. It's a very good result.
Chromatic aberration Sigma 24-105 mm f/4 Art
At this point the Canon does just a bit better than the Sigma. In the RAW files from the Sigma 24-105 Art sometimes there's visible lateral chromatic aberration, the most at a focal length of 24 mm and the least at 70 mm. Chromatic aberration is simple to correct with software. In the jpg files, there was no visible lateral chromatic aberration.
Conclusion Sigma 24-105 mm f/4 Art test @ APS-C
|WYSIWYG score: This table shows the performance of this lens if you store the files in the camera as jpg, where you have all available in-camera lens corrections applied. This score gives you for this lens/test camera combination: "What you see is what you get".