Sigma’s 18-35mm F1.8 that was released ten years ago became a cult favorite, particularly with the video crowd. Even full frame users often used it to help mitigate crop factors and because of the flexibility of having a zoom range AND a fast maximum aperture. Last year Sigma launched the 28-45mm F1.8 DG DN | ART lens, a lens I gave a fairly glowing review to because I felt it captured some of that “specialness” that is rare. That was a full frame lens, however, and as such was bigger, heavier, and more expensive than what APS-C shooters need. But Sigma is back with a true successor to the 16-35mm in the form of the 17-40mm F1.8 DC | ART. This is the first of the APS-C lenses in the current mirrorless era that has received the ART identifier (excepting a few very early primes that were definitely not ART worthy back in 2012 and 2013 when mirrorless was still an experimental oddity!) Has Sigma managed to recreate the magic that made people love the 18-35mm F1.8 so much “back in the day”? Is this lens a bargain at $829 USD ($1249 CDN)? We’ll explore that question in either my video review below or in the text review that follows.

https://youtu.be/vjokJlsYHNE

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Thanks to Sigma Canada (Gentec) for sending me a review loaner of this lens. As always, this is a completely independent review. *The tests and most of the photos that I share as a part of my review cycle have been done with the APS-C mode of my Sony a7RV.

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Some of the key selling features of the 17-40 ART include:

• Prime-like optical performance
• Full range of video features
• Custom (Fn) button
• Aperture ring with declick and iris lock options
• Internally zooming design
• Thorough weather sealing.

This is a slight deviation of the original zoom range, going a little wider (17mm vs 18mm) and a little longer on the telephoto end (40mm vs 35mm).

The APS-C crop factor of either Sony E, Fuji X, or L-mount is 1.5x (Sony is tested here, but I suspect we’ll see this lens on all these and perhaps Canon RF as well), meaning that 17mm has an effective full frame focal length equivalent of 25.5mm, which looks like this:

Meanwhile the 40mm end has a full frame equivalency of 60mm, which looks like this:

*Canon’s RF-S has a crop factor of 1.6x, so the effective focal range shifts to 27.2-64mm.

The advantage of an APS-C specific lens is that Sigma could produce a bigger zoom range (25.5-60mm) than what we saw on the 28-45mm full frame lens from last year. That could obviously be very useful for a lot of reasons.

The 28-45mm was a very large lens – over 153mm in length and weighing 950g – which leads us to the second big advantage of developing for the smaller sensor – the 17-40 ART, which still large, is considerably smaller and lighter than its full frame big brother…and even the DSLR era lens that it is the spiritual successor to.

The idea of a lens like this is that it is a “bag of primes” of focal lengths and optical performance while retaining a maximum aperture that is competitive with many prime lenses. You’ve got 24mm (ish), 35mm, 50mm, and even a slightly more telephoto 60mm equivalency. That’s very useful. And, in what we’ve come to expect from Sigma, the 17-40 ART does really deliver optically, be it from a distance or close up.

This is a not a perfect lens (it has some fringing and isn’t parfocal), but it is a very, very sweet lens.

Build and Handling

Thus far in the modern Sigma mirrorless era (starting in 2018), we’ve seen a large divide between most of the full frame lenses (ART and Sport) and the APS-C lenses, which have almost exclusively fallen under the Contemporary brand. That has typically meant relatively few features, a cheaper build, and minimal weather sealing (typically just a gasket at the mount), but that’s all different here. This is an ART lens, and, as such, it looks, handles, and feels like many of the full frame lenses from Sigma in recent years. The 17-40 ART has basically all of the features currently available on modern lenses.

That starts with the aperture ring. The aperture ring works great, giving you precise control at 1/3rd stops when in clicked mode, and gliding smoothly through the whole aperture range when declicked.

I understand that the Canon RF version will have a control ring rather than a traditional aperture ring, though the Sony E-mount version I tested had the traditional aperture ring.

By the way, I think that Sigma’s new fonts and logos look great. Very modern and upscale, and it is nice to see that ART badge on this lens.

On the lower left side of the lens is the Click/Declick switch which allows you to choose between those two options.

In declicked mode I could do smooth aperture racks without any visible steps, making this lens more attractive to video shooters.

On the right side of the lens is the iris lock. The iris lock will allow you to either lock into or out of the aperture ring. For those that want to use the aperture ring and not inadvertently switch into camera based aperture control, the lock can be engaged while you are in the aperture ring and keep you there. If you’re not an aperture ring person you can switch the lens into the A position and control it from within the camera. Engaging the iris lock while in A assures that you won’t inadvertently bump into manual aperture control.

The left side of the lens also has an AF/MF switch (always appreciated!) and two custom (Fn) buttons (one of the left side, one on the top so that they are accessible in either portrait or vertical shooting modes). You can assign the function of that button from within the camera.

This is an internally zooming lens, so there is no need for a zoom lock. Internally zooming lenses tend to be larger than externally zooming lenses for obvious reasons, but there are a number of key tradeoffs for that extra size.

• The lens length remains constant, making it easier to use on a gimbal (the weight balance doesn’t change)
• There is no risk of zoom creep, as there is nothing external to be affected by gravity.
• The zoom action is smoother and more precise
• There is less risk of getting dust or moisture in the lens because nothing is going in and out.
• The handling is better

I really think Sigma’s new fonts and logos have updated an already elegant design. This is a very classy looking lens, with glossier sections broken up by the ribbed textures of the rings. If you view from the back or sides, you’ll actually see an extra ribbed section in the middle that is purely aesthetic. It allows the glossier sections to be more uniform between the rings.3

The zoom ring is the closer of the two rings, with the manual focus ring further out. The manual focus ring is well executed, with wide ribbing and good damping. It makes for a good focus emulation, though as with all mirrorless autofocusing lenses this is focus by wire. Input to the focus ring is routed through the focus motor, and there are no hard stops at minimum focus or infinity.

This flows into the lens hood, which has a lock, a rubberized section for soft touch and a ribbed section for more grip when mounting or removing. Sigma’s lens hoods are nicer than just about any other brand. A padded nylon case is also included.

While I haven’t seen a cutout diagram of the weather sealing points, I do know that Sigma touts a professional grade of weather sealing on it. There is a gasket at the lens mount, a coating on the front element, and internal seals throughout the lens. Having internal zoom and focus doesn’t hurt, either.

The basic dimensions of the lens are 72.9mm (2.87″) in diameter and 115.9mm (4.56″) in length. It weighs in at 528g (18.62oz) on my scale and has an 67mm front filter thread. It’s not quite half the weight of the 28-45mm, but not far off. Sigma also notes that this lens is 30% lighter than the older 16-35mm F1.8.

The aperture iris has 11 blades, which helps keep the aperture iris shape circular even with the lens stopped down. That doesn’t automatically mean round specular highlights all across the frame, but rather than the aperture blades’ shape won’t be easily seen. Here’s a look at F2.8, for example.

The minimum focus distance of the lens is 28cm (11.1″), and the maximum magnification figure is achieved at 40mm and is a useful (nearly) 0.21x (1:4.8).

This combined with that F1.8 aperture allows for very nicely blurred backgrounds, and up close performance is quite good, though a little softer than if you back up another foot.

I love seeing a genuinely upscale APS-C zoom, a category that we’ve seen relatively few of. I can see this lens being a disrupter on all four platforms. I’d be very interested in seeing how it holds up on a 40MP Fuji sensor for example (an alternative to the 16-55mm F2.8 II?). How about on Canon RF, where there are relatively few premium APS-C lenses? There’s enough zoom range to be genuinely useful, and having a constant maximum aperture of F1.8 is genuinely intriguing.

Autofocus for Stills

This is another area where Sigma has made some key strides. Their initial offerings on Sony (and L-mount) featured STM focus motors, but Sigma has since released their more powerful, smoother HLA focus motor (High speed Linear Actuator). The HLA motor has much more torque/thrust than lenses equipped with the stepping motor, and I’ve found every lens equipped with the HLA motor to have excellent autofocus thus far.

The quick thrust of speed makes it effortless to stop action or snap shots on the fly. For example, one of my golfing buddies was walking through some dappled light up a trail between holes, but my camera was in a bag attached to my golf pull cart. I grabbed the camera quickly and snapped up to grab the shot before he walked out of the light.

Just in time!

The 18-35mm F1.8 actually didn’t have great AF back in the day (particularly for focus accuracy), but the 17-40 ART has fantastic accuracy.

Focus sound is basically nonexistent. The HLA motor is essentially silent even if I put my ear next to the lens. It is quiet enough that I literally looked up at the screen to make sure the lens was actually focusing. Focus speed is near instantaneous in most shooting situations, whether indoor or out.

Focus accuracy is good, too. I don’t really recall any shots during my review having been missed due to poor focus, and that was true even when I shot with smaller apertures.

Video AF

I also saw mostly good results for video work. Autofocus pulls were very fast and confident. No hunting or settling. Focus is fast and smooth, with nice damping. You can always slow it down in camera if you want a slower, more cinematic pull. Focus breathing seems well controlled, with only minimal subject size changes.

I had hoped that this lens would be parfocal, as back in the day the 18-35mm seemed to be everyone’s favorite video lens. Unfortunately that doesn’t appear to be in the case. If I focused at 17mm (F5.6) and then zoomed in to 40mm the focus has clearly shifted and focus is no longer accurate.

Faster autofocus from the HLA focus motor can help to mask that a bit, but there will be moments when everything is just slightly out of focus if you zoom while video recording.

My hand test where I alternately blocked the camera’s view of my face with my hand and then remove it went quite well, with nice damped transitions from my eye to the hand and back. The low focus breathing helps make this feel more cinematic.

I also found that in real world shots that focus changes tended to be more abrupt than what I would prefer. There’s a lot of thrust in this focus motor, but it probably would have been better to detune it a bit in video mode…particularly in a lens that will probably be highly desired for video work.

I found the 17-40 ART to be a great lens for filming my YouTube video episodes, as focus was rock solid during those episodes and the great zoom range allowed me some flexibility on framing.

Sigma’s HLA focus motors are great, though they are slightly limited on Sony by the fact that Sony limits bursts to 15FPS with third party lenses, so this one area where the 17-40 ART is less competitive on Sony. No such restriction applies on the other platforms, however.

Image Quality Breakdown

This remains a huge engineering feat, as Sigma has managed to broaden the zoom range from what was previously possible with a maximum aperture of F1.8. And, as per usual, they’ve done it in a fairly impressive fashion. The optical formula is is expectedly complex (17 elements in 11 groups), and that includes 4 SLD elements along with 4 aspherical elements. The MTF at 17mm is interesting; nearly flat through the midframe (and at an extremely high level) but with a surprisingly deep dive from there to the extreme corners. The 40mm MTF is a more typical “Sigma” look, with a fairly consistent performance all across the frame.

How does this compare to the older 18-35mm F1.8 lens? Sigma was kind enough to share.

Interestingly the two lenses have a fairly similar profile, though the new lens is just a little better everywhere.

I felt like the 28-45 DN had the “special sauce” where the colors, contrast, sharpness, and bokeh come together to produce a lens that makes very special images. I feel like the 17-40 ART isn’t quite as special, though that is mostly due to the difference in the sensors. APS-C just doesn’t produce the same kinds of shots at F1.8. At its best, though, this lens can produce pretty special images.

So how about full frame coverage? There’s no secret FF lens hidden here. Coverage is (expectedly) lowest at 17mm.

Coverage is somewhat better at 40mm, but there’s still some mechanical vignette that blocks the edges. Now obviously you can shoot in Super35 on a full frame camera, and a lens like this can be a good way to help mitigate a crop factor, but don’t plan on shooting the lens in full frame mode (particularly for stills).

The 28-45mm had next to no fringing, but that’s not true here. I was surprised by how much fringing I saw in the viewfinder when I shot my chart test.

When I moved over to my real world SLR test, I found the same picture with some fairly obvious blue fringing on shiny bits.

I also saw zero issues with LaCA (lateral chromatic aberrations), which shows up along the edges of the frame. All of the transitions here are very neutral.

Sigma went a little wider, and unsurprisingly that means a fair bit of distortion.

There is strong barrel distortion that required a +22 to correct. The good news is that the distortion is very linear, allowing for a very clean correction without any mustache pattern. I consider that alone a win. Vignette isn’t bad at all, requiring just a +38 to correct.

In the middle of the zoom range (28mm) the distortion has swapped to a pincushion style distortion, though fortunately it corrects in a linear fashion once again.

I needed to use a -6 to correct the distortion and a very mild +29 to correct about a stop of vignette. No big deal.

Unsurprisingly the pincushion distortion intensifies at the 40mm end, requiring a bit more correction (-11) but still correcting easily. Vignette remains impressively low, requiring just a +23 to correct.

I don’t love the longitudinal fringing, but nothing else stands out as being particularly off-putting.

So how about resolution and contrast? My formal tests are done on the APS-C mode of the 61MP Sony a7RV, which, at 26MP, matches the highest resolution currently available for APS-C on Sony. Fuji’s 40MP sensor will be a little more demanding.

The MTF suggests that this is a very sharp lens in the center and mid-frame areas at 17mm, F1.8, with a fairly steep drop-off in the corners. Is that what we see? Here’s a look at the test chart from which the crops come.

My findings are pretty consistent with what the MTF suggests, with a very crisp center and mid-frame, but definitely less sharpness in the corners (though contrast still looks pretty good). These crops are shown at 200%.

Real world shots follow a similar pattern, looking extremely good in the center and mid-frame, but noticeably softer near the edges.

Contrast creeps up a bit at F2, though it largely reinforces where the lens is already good. There’s a bit of improvement at F2.8 in the corners (where it is really needed), but corners never really get pin sharp. By F5.6 they are pretty good, but not on the level of the other areas of the frame.

Here’s a real world image at 17mm, F5.6 that shows amazing detail in the middle and good detail near the edge of the frame.

As per usual, sharpness peaks at F5.6-F8, and at F11 and then F16 (minimum aperture), you will get a bit less detail and contrast due to diffraction.

Moving on to 24mm shows a performance fairly consistent with what we saw at 17mm, though I think the corners show a bit more potential for sharpening. Here’s the center at F1.8 and F2.8:

And here is the upper left corner, which is still soft right at the edge, but you can see at F2.8 it’s looking quite sharp by the middle of the bill.

That last few percentage points never gets pin sharp, but I doubt that will matter much in the real world. This 24mm shot looks fantastic everywhere but that extreme corner, and I doubt anyone is going to be looking critically at that.

35mm seems to be very slightly less sharp than either of the previous positions, at least in the center and mid-frame.

Remember that this is relative, however. This is still a very sharp lens in real world shots at 35mm, F1.8.

This image looks nice and sharp, and has nice looking bokeh.

This second image at 35mm, F2.2, shows good detail and contrast along with a nicely soft background.

40mm looks fairly similar, with good sharpness and contrast which improves when stopped down a bit.

The corners look fairly good, though not exceptional. I would say that far corner sharpness is generally not a strength of this lens.

I found that I was generally very pleased with real world shots at 40mm.

I felt like global contrast even at 40mm, F1.8, looks great.

Shooting at 45mm is also going to give you the most dramatic combination of sharpness and bokeh. This is a lens capable of a very nice ratio between sharpness and softness.

In general I think the bokeh is very nice. There’s a very nice falloff from the plane of focus to defocus, and images have a nice pop to them. This image shows a nice dimensional quality.

Get close to your subject and you can really blur out the background, though up close contrast and detail isn’t fantastic.

Flare resistance also seems very solid. This morning shot has the sun right out of frame, and you can see that contrast has held up well.

In this shot the sun is right out of the frame but you can see there is no glaring into the frame.

There’s a lot to love here optically. It’s not flawless, but it consistently produced images I thought had a great “sparkle” to them.

Sigma has proven to be very successful at pushing the boundary of what’s possible at a particular aperture/focal length. Their engineering remains impressive. If you want to see more images, check out the image gallery for the lens here.

Conclusion

Sigma has done a brilliant job of updating a cult classic for the mirrorless era. The Sigma 17-40mm F1.8 DC | ART is improved in basically every fact over the 18-35mm F1.8 that I reviewed on Canon EF more than a decade ago. It’s smaller, lighter, has a bigger zoom range, has more features, better autofocus, and better optics. Not much to complain about there.

It’s ironic that this demonstrably better lens will very likely be somewhat less of a commercial success (though I’d love to be proven wrong). The market has shrunk and there are vastly more quality options available for different platforms these days. Sigma has shrunk the lens dramatically, and yet there will still be some who complain that it is too big. They’ve grown the zoom range, but invariably I’ll hear complaints that it doesn’t go to 16mm, or to 50mm. In an era where we are spoiled for choice, people tend to be a little less easily wowed than what they once were.

But if you stop and appreciate this lens, you’ll recognize that, while imperfect, this is a completely unique lens that is going to make a lot of sense for a lot of people. It has a big enough zoom range to be useful, and having that F1.8 aperture does dramatically change the look of images relative to a more pedestrian F2.8 aperture (which is 1 1/3rd stop slower). It will allow you to keep the ISO down, and if you happen to be an APS-C wedding or event shooter, the 17-40 ART needs to immediately go on your short list. It really is like having a bag of primes in one lens. And, at a price tag of $829 USD, this is a lot of lens for the money.

Pros:

• Improved over the 18-35mm F1.8 in every way
• Extremely useful zoom range
• Beautifully made
• Feature rich
• Internal zoom and focus makes for great handling
• Thorough weather sealing
• Ability to declick aperture
• HLA focus motor is extremely quiet and has a lot of thrust
• Aperture racking works well
• Excellent focus accuracy
• Very low vignette throughout
• Extremely sharp lens
• Beautiful bokeh
• Good flare resistance

Cons:

• Not parfocal
• More fringing than what I would like
• Strong barrel distortion at 17mm
• Extreme corners are rarely pin sharp

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GEAR USED:

Purchase the Sigma 17-40mm F1.8 ART @ B&H Photo | Adorama | Amazon | Camera Canada | Amazon Canada | Amazon UK | Amazon Germany

Purchase the Sigma 28-45mm F1.8 ART @ B&H Photo | Nuzira | Adorama | Amazon | Camera Canada | Amazon Canada | Amazon UK | Amazon Germany

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