Review Sigma 18-35mm f/1.8 DC HSM Art (C APS-C)
Just the announcement of the Sigma 18-35 mm Art unleashed on the Internet an explosion of enthusiastic responses about the specifications and speculations about the price of this lens. This Sigma 18-35mm f/1.8 Art lens is a high-quality alternative to the all-round kit lens, offering higher image quality and a fast constant f/1.8 aperture. It is the world's first f/1.8 APS-C standard zoom lens.
If we neglect the slightly smaller field of view range of the Sigma 18-35mm, compared to a 24-70 mm zoom lens on full frame camera, then the Sigma 18-35 mm f/1.8 is a serious candidate to reach the image quality of a full frame camera, using a cheaper and lighter APS-C camera. This can save you a lot of money. The full frame camera and the best full frame lenses all have a price (far) above the 1,000 Euro. No wonder there are many photographers that take some time to decide whether they will buy such a camera, or will remain using an APS-C camera and invest in better glass.
"Nowadays there are various APS-C cameras with exceptionally high image quality for sale with a suggested retail price of thousand Euro or less. We would like to provide a matching lens in terms of price and quality. The Sigma 18-35 mm f/1.8 Art seemed also to us an attractive offer. "
There was a Sigma 18-35 mm 1.8 Art pre-production model with Canon mount lenses available. We attached it immediately to our Canon 650D.
Sigma 18-35mm f/1.8 DC HSM A @ Canon 650D
Sigma 18-35mm f/1.8 DC HSM A @ 18mm, f1.8, 1/800 s, 100 ISO
|The Sigma 18-35 mm f/1.8 Art has a field of view that varies from slight wide angle to standard. This corresponds to the field of view of a 29-53 mm zoom lens on a camera with a full frame sensor. This field of view range and the fast, constant f/1.8 aperture make the Sigma 18-35 Art an ideal lens for concert, holiday, street, wedding or report photography.|
The black appearance and the high quality of workmanship of the lens are the same as those of the Sigma 35 mm f/1.4 lens. During the test period we showed this lens to several photographers. They all loved the looks and feel of it.
The Sigma 18-35 mm f/1.8 Art is a good alternative to the standard kit lens. The use of plastic, "Thermally Composite" (TSC), for the lens body, reduces the weight of the Sigma 18-35 mm Art. Of course you cannot compare this lens with a standard kit lens. With a length of about 12 centimeter, a filter size of 72 mm and a weight of 810 grams, the Sigma 18-35 mm Art is larger and heavier than average APS-C standard zoom lens. For professional photographers that use a full frame camera with a 24-70 mm zoom lens, its length and weight are just right.
|The Sigma 18-35 mm f/1.8 Art features internal focusing, what makes that the length of the lens does not change, and the filter thread will not rotate when focusing. Even when you are zooming in or out, the lens will remain unchanged in length. Especially when you do close ups, where the front lens can approach up to 8 cm of the subject, this is nice. The AF is an USM-type, which not only results in fast and precise focusing, but it also offers the possibility to manually overrule the AF. The AF is accurate, silent and fast. Because of the large aperture, the AF is also accurate in low light. ||Greetings from Holland. Click (2x) on above image for a cropped image at 100%. |
This gives an impression of both the sharpness and the background blur.
Resolution Sigma 18-35mm f/1.8 DC HSM Art
When it comes to sharpness, the Sigma 18-35 mm f/1.8 Art comes out as one of the best of all the lenses we have tested so far on a Canon camera with an APS-C sensor. This is true for zoom lenses as well for lenses with a fixed focal length.
The sharpness at maximum aperture is really high. At a focal length of 22 mm and 35 mm we measure the highest sharpness at f/4. The sharpness at the edges is at a 35 mm focal length actually as high as in the center. At the shorter focal lengths we measure at f/1.8 in the corners a slightly lower resolution then in the center. But even then, the sharpness of the corners is always higher than 1500 LW/PH, which is still very good. In the pictures we have shot outside, we could not see the "lower sharpness in the corners" with the naked eye. But we could see that the sharpness in the corners at f/4-f/5.6 is equal to the sharpness in the center.
Sigma USB dock
|With the Sigma Art, Contemporary and Sports lenses you have the option of using an USB dock (Available for 55 euro). You can download the latest lens firmware for the Sigma 18-55mm f/1.8 and also adjust the focus in combination of your camera with this lens. We will describe our experience with the Sigma 18-35 mm Art in the second part of our Sigma USB dock review. |
|Given the large aperture of the Sigma 18-35 mm Art, it is no surprise that there is some visible vignetting at the largest aperture. Stop down for two stops, and you're still at f/4, which is the initial opening of some kit lenses, and the vignetting is gone. Canon cameras offer, in contrast with Nikon cameras, only the ability to correct for vignetting of their own brand lenses. The vignetting is slightly larger in the jpg files that are saved in the camera, then in the RAW files. We have seen this more often and probably this has to do with the higher contrast in the jpg files that get when we have stored in the standard picture style in the camera. |
If you compare the vignetting shown by the Sigma 18-35 Art in RAW files from the Canon 650 to the vignetting of fast zoom lenses in RAW files on a camera with a full frame sensor, then you will see they look familiar.
You can manually or with the use of software correct the above easily.
|The distortion of the Sigma 18-35 mm Art changes from light barrel at a focal length of 18 mm, in to pincushion at a focal length of 35 mm. These are not unusual values for a zoom lens with this range and in use you will hardly notice it. It is also simple to correct distortion using lens correction profiles in Photoshop or Lightroom. |
|The Sigma 18-35 mm Art has 9 rounded blades that yield a round a nice bokeh bright light source in the background. Both background blur and foreground blur do - in terms of character - strongly reminiscent of the OOF ("Out of focus") of a lens on a camera with a full frame sensor. There is a pattern visible in the bokeh. We see that more often with lenses with a high resolving power. Below is a comparison of two 100% crops of test images made with a camera with a full frame sensor and with the Sigma 18-35 mm f/1.8 on the Canon 650D. If you don't enlarge both images up to 100%, as is shown here, the difference is even smaller. |
At maximum aperture the bokeh changes in the corners into so called "cat's eye bokeh", due to vignetting, as you can see in the picture right below. Cat's eye bokeh is a common phenomenon for lenses on a camera with a full frame sensor.
|With the Sigma 18-35 mm f/1.8 Sigma's Art, the designers did a good job. If there is a bright light source just outside the image, then you have no problems with the flare. It is even better if you use the included lens hood. If you are shooting straight into the Sun, then there is a small zone around the Sun where flare (diminished contrast) is observable. With effort we could find in our test shots a rainbow-like ghost image that we circled in red in the cropped image on the right. We think that there is currently not a better zoom lens then this. There are many lenses with a fixed focal length that suffer more from flare and ghosts. This seems to me an important consideration when you like HDR, night photography or concert photography. |
We've tested for flare at f/4, see also the flare section in the Sigma 18-35mm f/1.8 Art review by Lenstip.
Chromatic aberration Sigma 18-35mm f/1.8 DC HSM Art
You will not encounter lateral chromatic aberration, magenta and blue-green edges in strong contrast transitions in the corners of the image, when you use this lens. And even longitudinal chromatic aberration - or color bokeh- , purple and green edges sharp contrast transitions in focus areas of an image, is very well suppressed. But slightly less than the Sigma 35mm f/1.4. If you move your mouse over the graph of the lateral chromatic aberration, you will see an example of color bokeh in one of our test shots. This is the worst case we encountered. Color bokeh only occurs with fast lenses and it disappears if you choose a smaller aperture. At f/2.8 or smaller you will see no color bokeh.
Conclusion Sigma 18-35mm f/1.8 DC HSM Art review
|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". |