This is an in-depth review of the Sigma 18-35mm f/1.8 DC HSM Art lens, world’s first constant f/1.8 zoom lens for DSLR cameras that was announced in April of 2013. Despite the recent trend of manufacturers to move their customer base to full-frame format, Sigma took a bold move and announced the professional-grade Sigma 18-35mm f/1.8 Art for DX/APS-C format only. With a focal range equivalent to 27mm-52.5mm in 35mm format, the lens provides a good range to work with for a variety of different needs and applications. And with its fast constant aperture of f/1.8, the Sigma 18-35mm opens up opportunities to shoot in low-light situations, something that was previously only possible with fast aperture prime lenses. Lastly, Sigma’s pricing of $799 MSRP for the lens made it the top choice in terms of value when compared to pro-grade lenses such as the Nikon 17-55mm f/2.8G DX, which sells for almost twice as much and does not offer the same low-light advantages.
The Sigma 18-35mm f/1.8 DC HCM is a technological marvel, because it is the first zoom lens in history with such a wide / fast aperture. On top of that, Sigma used many high-end features and components that are usually only available on pro-grade full-frame lenses. First, the lens comes with a hypersonic motor (HSM), which provides silent and fast autofocus. Second, the lens has a very complex optical formula that consists of a total of 17 lens elements in 12 groups, with 4 aspherical and 5 low-dispersion elements. Third, it has a metal mount and a thermally stable composite barrel, which offers greater elasticity than polycarbonate and offers minimal thermal shrinkage with exceptional hardness, something Sigma has only recently started providing on its new generation lenses. And lastly, being an “Art” series lens, it is fully compatible with Sigma’s USB dock that allows micro-adjusting autofocus parameters.
1) Lens Specifications
- A large-aperture APS-C format standard zoom lens for digital SLR cameras that creates an entirely new standard for zoom lenses
- Exemplifying Sigma’s design know-how and advanced production technologies, this innovative lens offers the highest level of craftsmanship
- Covering the angle of view offered by several large-aperture, fixed focal length lenses, this lens combines advanced flexibility with uncompromising performance
- Superior functionality across the lineup, thanks to Sigma’s proprietary new A1 MTF measuring system
- A refined, integrated design made with the photographer in mind
- Newly developed exclusive software and USB DOCK to make customization simple
- Available for Mounts: Sigma, Sony, Nikon, Pentax, Canon
- Focal length: 18-35mm
- Maximum aperture: f/1.8
- Minimum aperture: f/16
- Lens construction: 17 elements in 12 groups
- Angle of view: 76.5° – 44.2°
- Closest focusing distance: 28cm/11.0in.
- Maximum reproduction ratio: 1:4.3
- No. of diaphragm blades: 9 (rounded)
- Filter/attachment size: 72mm
- Diameter x length: 78mm x 121mm / 3.1in. x 4.8in.
- Weight: 810g/28.6 oz.
2) Lens Handling and Build
Sigma has put a lot of effort into making the new generation lenses attractive both in terms of design and function, and the Sigma 18-35mm is not an exception. Similar to the Sigma 35mm f/1.4 Art, the lens gives a different sense of quality to it when compared to previous generation Sigma lenses. The craftsmanship of the lens is indeed excellent. Starting from the rugged brass mount that smoothly connects with the metal barrel, to the smooth rubber focus ring in the front, you won’t get a feeling of a cheap lens that we are so accustomed to when usually dealing with APS-C/DX lenses. The metal barrel is made of a special Thermally Stable Composite material, which offers exceptional hardness, better elasticity than polycarbonate and minimal thermal shrinkage. This basically means that the lens should easily withstand extremely hot and cold temperatures without damage or potential performance degradation. While I could not test the lens in hot temperatures, I did take it out during a very cold morning when the temperatures peaked -5F (some of the snow images in the review were taken during that morning). The lens performed very well during and after the shoot, autofocus continued to function without any problems, and both zoom and focus rings operated smoothly without getting stuck. In short, the build quality of the Sigma 18-35mm is outstanding. My only gripe is lack of a rubber gasket on the mount to prevent dust and other debris from getting into the camera. For some reason, Sigma never includes one on its lenses, which is unfortunate.
The handling of the lens is also superb, although that can depend on whether you are comfortable with a reverse rotation of the focus ring. The zoom ring follows similar clock-wise rotation from short to long focal lengths as Nikon’s DX lenses, but its focus ring is reversed. So to move from close focus to infinity, you would have to rotate the focus ring counter clock-wise. Aside from this ergonomic difference, I have not seen any serious issues with handling (and Canon users might prefer how the focus ring works, because Canon lenses work the same way). Yes, the lens is indeed quite heavy at 810 grams, but considering its fast speed, metal construction and a total of 17 lens elements, I doubt Sigma could have made it lighter. That said, it certainly does feel front-heavy when mounted on lightweight DX cameras like Nikon D5300. At the same time, its long barrel actually makes it easier to balance it out on lightweight camera bodies when it is hand-held. The zoom ring is smooth and has some nice resistance to it, while the focus ring is also very smooth, albeit with a little less resistance. Similar to many Nikkor lenses, there is a switch on the side of the barrel that allows to move the lens from autofocus to manual focus operation. The middle portion of the barrel (which is nicely threaded underneath for better grip), along with the front part and the filter thread are plastic. Sigma probably decided to use the lighter material to decrease the weight of the lens. The supplied hood is also plastic and can be mounted regularly, or in opposite direction to save camera bag space. Once mounted on the lens, it stays secure and does not wobble.
3) Use on Full-Frame
Some DX / APS-C lenses are known to work quite well on full-frame cameras, with some vignetting that can be removed in the corners (the Nikon 35mm f/1.8G is a good example of such lens). The Sigma 18-35mm f/1.8G is not a good candidate to be mounted on a full-frame camera, especially at the shortest end of the focal length. Take a look at how the image turned out when I shot it at 18mm on the Nikon D800E:
When I saw the above, I changed the setting on my Nikon D800E to switch to DX crop mode when the lens was mounted on it.
4) Autofocus Performance and Accuracy
Thanks to the fast hypersonic motor, the lens acquires focus quickly and silently. I compared the AF speed of the Sigma 18-35mm f/1.8 to the Nikon 50mm f/1.8G and while the Nikon seemed to be a tad faster, it was definitely noisier. Also, it is important to note that unlike older lenses that required cameras to have a built-in autofocus motor, the Sigma 18-35mm has an integrated focus motor, which means that autofocus will work on entry-level cameras like Nikon D3300 and D5300. With lenses with built-in focus motors, you do not have to worry about buying a higher-end DSLR just to be able to utilize autofocus anymore.
In terms of autofocus accuracy, the lens behaved rather unpredictably at times. While most of the images were in focus, sometimes the lens would simply refuse to acquire correct focus on both the Nikon D5300 and the Nikon D800E (in DX crop mode). And when the light conditions were less than ideal pressing the AF-ON button repeatedly to force the lens to reacquire focus would not help either. Occasionally, I would extend my hand at a close distance, force the lens to acquire focus, then refocus on the subject. I don’t know if this has to do with Nikon firmware not playing well with Sigma, or if it is Sigma’s AF motor that is unreliable, but it sure was disappointing to take a shot only to find out that the lens focused on the background. Utilizing the center focus point and using the focus and recompose technique in low-light and high-contrast situations seemed to yield better results.
5) Lens sharpness, contrast and color rendition
As with other lenses, I put the Sigma 18-35mm f/1.8 through a stress test in my Imatest lab to find out what its sharpness looks like when the lens is used on a 15.3 MP equivalent sensor. Since I always test lenses with my Nikon D800E camera for consistency reasons, I had to shoot the 18-35mm in DX mode, which yields smaller resolution. To be able to compare results with full-frame lenses, the results were multiplied by a factor of 1.533 (crop factor). I do realize that performing tests on the latest generation 24 MP APS-C sensor cameras might be a better choice, since higher pixel density sensors certainly do reveal more lens flaws. However, putting different cameras into the mix with potentially different image processing pipelines, AA / no AA and other variables would yield completely different results, making it hard or even impossible to compare DX/APS-C to full-frame lenses. For that reason, I decided to use the Nikon D800E for testing both FX and DX lenses.
As I reveal below, the sharpness performance of the Sigma 18-35mm f/1.8 is very impressive for a zoom lens with such wide aperture. Microcontrast levels are very high and the lens does not suffer from heavy field curvature issues like many other wide angle lenses do.
In terms of colors, the lens produces beautiful, vivid colors, similar to those you would get from high-end Nikkor lenses with optical coatings.
Some Technical Info:
Camera: Nikon D800E
Focus Method: Live View Contrast Detect + Manual Focus
Image Format: 14-bit RAW
Workflow: Import RAW into Lightroom 5 with default settings, Export in JPEG format, 100% Quality
Analysis Software: Imatest 3.9, Master Edition
Testing was performed at f/1.8, f/2, f/2.8, f/5.6, f/8, f/11 and f/16 apertures
6) Sigma 18-35mm f/1.8 MTF Performance
Let’s take a look at the sharpness capabilities of the Sigma 18-35mm f/1.8 DC HSM in detail. Here is the lens performance at the short end of the zoom range, at 18mm:
The lens shows very impressive performance at 18mm both in the center and in the mid-frame. The corner performance is a little weaker, but regains sharpness at just f/2.8. Peak performance is reached at f/2.8, which is remarkable.
Let’s take a look at what happens when we zoom in to 24mm:
The performance at 24mm is even more impressive, yielding very high levels of mid-frame and corner performance. Peak performance is again reached at f/2.8.
And finally, here is the lens MTF at 35mm:
Although the center performance drops a tad, mid-frame and corners look the best at 35mm, so there is more balance of sharpness across the frame.
The consistency of performance throughout the focal range is very impressive. The Sigma 18-35mm f/1.8 is one of the best DX lenses I have tested to date. In comparison, neither the Sigma 30mm f/1.4 Art, nor the Nikon 35mm f/1.8G lenses can reach such high performance levels at large apertures.
The bokeh performance of the Sigma 18-35mm f/1.8 is pretty good at f/1.8, especially towards the longer focal lengths. As you zoom out back to 18mm, getting background blur gets more difficult due to shorter focal length. Still, I found the bokeh performance of the lens to be quite good when photographing subjects up close, as demonstrated in the following image samples:
Vignetting levels are very low for an f/1.8 lens. That’s another surprising find, as I initially expected to see much worse vignetting throughout the focal range. Wide open at 18mm, vignetting is only at about 1.39 stops and it increases as you zoom in towards 35mm. At the long end, vignetting reaches about 1.65 stops, which is still very impressive:
9) Ghosting and Flare
The effect of ghosting and flare depends on the position of the sun/bright spot and the focal length. Here is a sample image shot at 18mm, f/16:
At such small apertures, expect to see 18-ray sunstars, thanks to the 9-blade diaphragm. Some ghosting and flare is visible at such a wide angle, but it is not hugely distracting. As you zoom in towards 35mm, ghosts and flare are more magnified, but a little less defined:
Distortion levels are moderate. At 18mm, there is barrel distortion of -1.25%, which changes to pincushion distortion when zoomed in towards 24mm. Pincushion distortion is at its strongest level at 35mm, where it reaches about 1.52%, as shown in the graph below:
Since Lightroom and Adobe Camera RAW already have a built-in profile for the Sigma 18-35mm f/1.8 lens, you can easily fix distortion with a single click using the lens corrections sub-module.
11) Chromatic Aberration
Lateral chromatic aberration levels are pretty moderate at short focal lengths, averaging a little over a pixel. As you zoom in, CA levels drop and reach their lowest at 35mm:
Lateral chromatic aberrations are generally not a problem and can be easily fixed in Lightroom and Photoshop. Typical for fast aperture lenses though, longitudinal chromatic aberration is visible at f/1.8 in front of and behind the focused area.
The Sigma 18-35mm f/1.8 has no equivalents to compare to, so I decided to put it against the Sigma 30mm f/1.4 DC HSM Art lens, along with the Nikon 35mm f/1.8G (both APS-C) that I had at the time of testing.
12) Sigma 18-35mm f/1.8 vs Sigma 30mm f/1.4
Let’s take a look at how the Sigma 18-35mm f/1.8 Art compares to the Sigma 30mm f/1.4 Art @ 35mm and 30mm:
Looks like Sigma’s own 30mm f/1.4 prime cannot compete with the Sigma 18-35mm f/1.8 zoom. The difference in performance is quite evident right at f/1.8, where the Sigma 18-35mm is better not only in the center, but also significantly sharper in the mid-frame and the corners. In fact, the 30mm f/1.4 Art is quite disappointing in comparison – its peak sharpness is reached at f/5.6, while the 18-35mm is extremely sharp at f/2.8!
13) Sigma 18-35mm f/1.8 vs Nikon 35mm f/1.8G
Let’s take a look at how the Sigma 18-35mm f/1.8 fares against the Nikon 35mm f/1.8G:
It is pretty clear that the Sigma 18-35mm f/1.8 is a better candidate for low-light photography than the Nikon 35mm f/1.8G. The Sigma 18-35mm has amazing wide open performance that the Nikon 35mm f/1.8G can only catch up to at f/2.8, and even then it cannot quite match Sigma’s corner performance. The Nikon 35mm f/1.8G produces impressive center and mid-frame sharpness at f/2.8 and smaller, but its corners cannot match what Sigma can do at any aperture.
When Sigma announced the 18-35mm f/1.8 DC HSM lens, it made big headlines all over the Internet. Being the first ever f/1.8 zoom lens, it caught a lot of attention from media and instantly became a success story for Sigma. However, I had my doubts about its performance, thinking that Sigma had to compromise the fast aperture with rather average performance. When I finally received the Sigma 18-35mm f/1.8 back in November of 2013 and took it with me on a trip to New York and then to New Mexico, it continued to surprise me with its superb sharpness, beautiful colors and impressive build. The lens went through quite a bit of stress, being exposed to bone chilling -5F degree temperatures and it continued to produce images without any problems. While I had a few other lenses with me, I just did not want to take it off the Nikon D5300 DSLR that I was testing at the same time. With its wide to normal focal length coverage and a fast f/1.8 aperture, it was a versatile lens that I used for photographing different subjects in various lighting conditions. The Sigma 18-35mm f/1.8 felt totally different than handling the typically slow f/3.5-5.6 zoom lenses, especially once I realized how sharp it was at its widest aperture.
The Sigma 18-35mm f/1.8 Art deserves the highest of praises for being such an amazing lens. Being a full-frame shooter, I am saddened by the fact that such lens does not exist for FX, but I also realize that a lens like this would have probably been twice larger in size and much heavier, perhaps making it rather prohibitive to use on full-frame cameras. My main complaint is its autofocus accuracy issues that I have encountered when shooting with Nikon camera bodies. While my lens sample did not seem to have any front/back focus issues, it would occasionally miss focus. Shooting with the D5200 that has a rather small viewfinder, it was impossible to tell if focus was accurate or not until I reviewed images. I am not sure if such autofocus accuracy problems are related to Sigma’s AF motor, or it is some sort of an incompatibility with Nikon’s DSLRs, but I very much hope that Sigma addresses AF accuracy issues via firmware soon.
Overall, I am very impressed by the performance of the Sigma 18-35mm f/1.8 DC HSM. It is certainly a game changer, not only because it is the first f/1.8 zoom lens in history, but also because it is a stellar performer. I cannot wait to see more lenses like this from Sigma in the future. If I owned a DX / APS-C camera, the Sigma 18-35mm f/1.8 would have been one of my first candidates for everyday photography.
15) Where to buy and availability
B&H is currently selling the Sigma 18-35mm f/1.8 DC HSM lens for $799 (as of 01/14/2014).
16) More Image Samples
All Images Copyright © Nasim Mansurov, All Rights Reserved. Copying or reproduction is not permitted without written permission from the author.
Sigma 18-35mm f/1.8 DC HSM Art
- Optical Performance
- Bokeh Quality
- Build Quality
- Focus Speed and Accuracy
- Size and Weight
Photography Life Overall Rating