Landscape photographers looking for a wide-angle zoom lens with exceptional sharpness and performance from 12mm-16mm.
Not so good for
Photographers looking for excellent performance across the entire focal range and photographers who prefer to shoot with a lighter kit.
The Sigma 12-24mm F4 offers impressive optical performance at the short end of its focal range, with excellent AF performance. Unfortunately, central sharpness at all focal lengths, and overall sharpness at the tele end suffers relative to its best peers. Severe focus shift at longer focal lengths require you to focus the lens at the shooting aperture, which can be cumbersome, and will also come at a cost to corner sharpness. Other optical properties, like CA, vignetting, and distortion are extremely well-controlled if not class-leading. If you’re looking for a wide-angle zoom with very nice performance from 12mm-16mm then this lens is an exceptional value.
The Sigma 12-24mm F4 DG HSM Art was first announced September 16th, 2016. This is Sigma’s widest zoom lens offering to date and joins Sigma’s growing list of Art lenses. The lens is priced at just under $1600, which makes it a fierce competitor to Canon’s EF 11-24mm F4L USM lens which is priced at just under $3,000.
The Sigma is available in Canon, Nikon F (FX) and Sigma SA Bayonet mounts and will most likely appeal to landscape and architecture photographers that are looking for an extremely wide field-of-view (12mm gives around a 122° diagonal field of view).
The looming question is: does the extreme difference in price effect the build quality and performance of the Sigma? In this review we will be looking at the Sigma’s performance and just how it stacks up against the Canon 11-24mm F4L.
If you’re an APS-C shooter, the Sigma can be utilized on that platform with an equivalent focal length of 19-38mm and an equivalent aperture of F6.4. It’s worth noting however that Sigma already offers a considerably less expensive 10-20mm F3.5 which would be a 16-32mm F5.6 equivalent, which would be a much better wide-angle option. For this reason we’re not going to consider this lens for use on APS-C in this review.
Sigma 12-24mm F4 DG HSM Art Headline Features
- 12-24mm focal length
- F4 maximum aperture
- Ring-type Ultrasonic Focusing
- Available in Canon EF, Nikon F (FX) and Sigma mounts
|Sigma 12-24mm F4 DG HSM Art||Canon EF 11-24mm F4L USM|
|Lens Type||Wide-Angle Zoom||Wide-Angle Zoom|
|Filter Thread||None||None (rear insert-type)|
|Lens Mount||Canon, Nikon F (FX), Sigma SA Bayonet||Canon EF|
|Minimum Focus||0.24 m (9.45″)||0.28m (11″)|
|Diaphragm Blades||9 (rounded)||9 (rounded)|
|Special Elements/Coatings||Super Multi-Layer Coating, F-Low Dispersion and aspherical elements, including an 80mm large-diameter molded glass aspherical element||Super UD, UD, and 4 Aspherical Elements, SWC, Air Sphere, and Fluorine Coatings, Rear element fluorine coatings|
|Motor Type||Ring-type Hypersonic||Ultrasonic|
|Full Time Manual||Yes||Yes|
|Weather Sealing||Dust and Splash Proof Construction with rear rubber gasket||Full Weather Sealing|
|Zoom Method||Rotary (extending)||Rotary (internal)|
|Weight||1151g (2.54 lb)||1180g (2.60 lb)|
|Dimensions||132mm (5.2″) x 102mm (4.0″)||132 mm (5.2″) x 108 mm (4.25″)|
|Hood Included||Yes (built in)||Yes (built in)|
The Sigma and the Canon share a rather large number of the same features with respect to lens design. The main differences between the two lenses are highlighted in green. The Canon has a slight edge over the Sigma in terms of build quality with full weather sealing, where the Sigma offers a ‘moisture resistant’ rubber gasket on the lens mount and water-repellent coatings on the front and rear lens elements.
Both lenses are very heavy and are nearly identical in size and shape, and both feature built-in lens hoods. Neither lens accepts standard screw type filters, but the Canon has a slot to accept rear gel filters. The Sigma has that familiar Art build that feels very robust in hand but lacks the same ‘sealed’ feeling that the Canon lens provides due to its water resistant external construction.
The Canon has a slight advantage over the Sigma in terms of the zoom method as the Sigma has an external extending zoom whereas the Canon’s is internal. Being that the Sigma isn’t fully weather sealed this could be a weak point in the design in terms of moisture penetrating the lens during adverse or wet weather conditions.
With these specifications in mind, we will now be looking at how well the Sigma performs to determine how it fairs in our head-to-head comparison with the Canon 11-24mm F4L.
In the following sections we will use DxO data and real life samples to determine how the Sigma and the Canon lenses compare to one another and to determine just how the Sigma 12-24mm performs.
|Sharpness||The Sigma 12-24mm performs very well wide open at 12mm and even better once the lens is stopped down to F8. Sharpness is generally best from 12mm-16mm when the lens is stopped down to F5.6. As you zoom in from 16mm to 24mm overall sharpness wide open decreases a great deal. In this range we see the best performance when the lens is stopped down to F8. Corner sharpness is very good on the wide end, but drops off as you zoom.|
|Chromatic Aberration||The Sigma does a very good job of handling chromatic aberration throughout the focal range, even when shot wide open. As you stop the lens down or zoom in you even see a slight improvement in the handling of CA.|
|Vignetting||With respect to vignetting the Sigma does a phenomenal job throughout the focal range, even when shot wide open. When the lens is stopped down to F8 the vignetting completely disappears across the entire focal range.|
|Distortion||The Sigma suffers from slight barrel distortion at 12mm, but that is to be expected at that wide of a focal length. By 16mm it all but disappears. The distortion at 12mm appears fairly complex, likely making it difficult to correct, but it’s so subtle you’re unlikely to be bothered by it.|
|Transmission (T-Stop)||The lens’ F-number is a theoretical value, and the actual light transmission value, known as the T-stop, is always fractionally lower due to light losses within the lens. Lenses with more elements, like a complex zoom, tend to be slightly more effected. The measured T-stop for this lens is around T4.6-4.8, which means the lens is letting through a bit less light than the F4 rating suggests.|
How does the Sigma 12-24mm DG HSM ART compare against the Canon EF 11-24mm F4L?
The Canon 11-24mm F4L is a fairly well known commodity with many claiming that it’s the sharpest wide-angle zoom lens on the market. In truth it really does live up to this hype as it out performs the Sigma lens in many respects.
In terms of sharpness the Canon lens is one of the sharpest wide-angle lenses we’ve ever seen at its wide end, out-performing the Sigma wide open and across nearly every aperture, particularly in central sharpness. As you progress through the focal lengths you start to really see the Canon lens pull away as the Sigma increasingly requires stopping down to achieve comparable sharpness across the frame. By 16mm the Sigma performs markedly lower than the Canon lens in terms of sharpness, even after you stop the lens down to F5.6. At 24mm the differences between the Canon and Sigma are night and day. To achieve results that are close to the Canon lens in terms of central sharpness shot at F5.6, you need to stop the Sigma down to around F8, which introduces enough diffraction to still keep it well behind the Canon. This will also impact your ability to use the longer end of the lens in low-light situations as shooting wide-open yields fairly poor results.
The Sigma lens does, though, have the upper hand in terms of vignetting, chromatic aberration (CA) and distortion. CA at the widest end of the focal range sees the Canon lagging behind, exhibiting quite a bit of CA (check out the right side of this image at 1:1), which may be a little difficult to correct perfectly, given its non-linear behavior towards the edge of the frame.
In terms of vignetting the Canon suffers from a 3.7 stop fall off in the extreme corners of the lens while the Sigma only has a 2/3 stop fall off at at their widest focal lengths. By F8 the vignetting all but disappears in the Sigma while it persists at 2/3 of a stop in the corners of the Canon lens all of the way through F22, though you do see a marked decrease by F11. As you zoom the Canon out from 18mm-24mm the vignetting decreases but only disappears by F11 in the Canon lens.
Both the Canon and Sigma perform fairly well with respect to distortion, with the Sigma lens edging out the Canon lens at nearly every focal length, but markedly so at the widest end of the focal range. That said, the Canon’s distortion is less complex, so is likely to be easier to correct, in ‘post.’
Real World Tests
Note the shots above were focused at maximum aperture for each focal length, then shot increasingly stopped-down. This results in some focus shift at longer focal lengths that we’ll demonstrate further down the page.
When comparing the two lenses in our real world tests we see that Sigma suffers in sharpness throughout nearly the entire focal range when the lens is focused wide open, but especially from 20mm to 24mm. At the widest end the Sigma is nearly on par with the Canonand actually performs better with respect to . As we mentioned above the Sigma’s performance declines at and , especially when compared to the Canon lens, and doesn’t help matters. Although the DXO data suggests the Sigma should sharpen up in the center by F8 at 24mm, we believe we’re not seeing this due to the Sigma’s rather severe focus shift at longer focal lengths. DXO’s findings are based off of selecting the optimal shot from series’ of meticulously manually focused shots, and while both approaches have their merit, the results you’ll achieve will depend on your focus method (more on this later).
In terms of corner sharpness the Sigma performs very well when compared to the Canonwith both lenses exhibiting about the same level of sharpness (the Sigma’s a tad sharper on the left while the Canon’s a bit sharper on the right). As the DXO data suggest, we see that the Sigma performs very well with respect to the handling of CA in the corners of the lens as well. At 24mm we see the Sigma’s decrease a fair bit when it’s shot wide open at F4, which agrees with DXO data. Once the lens is , the corner performance improves and is nearly on par with the Canon lens shot the same focal length. But F8 brings with it more diffraction, and this shows in the softer center performance relative to the Canon at F5.6 (which is all the Canon needs to be stopped down to for optimal performance).
It’s worth noting that the perceived peripheral sharpness in the Canon lens may be slightly decreased due to the rather extreme. However, ACR (and other forms of post processing software) will be able to remove the majority of it, thus removing the color artifacts and improving image quality.
The Canon lens performs very well across all focal lengths, so well in fact that it often reaches its peak performance by F5.6, and becomes diffraction limited thereafter (on a 5DS R). It’s a feat of engineering. That said, the Sigma turns in comparable, if not sometimesin our real-world tests, performance at the edges at its wider end. But the same can’t be said for its central performance, where it falls behind at all focal lengths, be it , , , , , and . Sigma’s parity (or lead, depending on your specific copy or the side of the frame you’re looking at) in edge performance wide open at the wide end is , where the Sigma must be to F8 to match the edge performance of the Canon at F5.6, albeit fall well behind in .
We discovered that much of the drop – or lack of improvement – in central sharpness upon stopping down was due to focus shift due to the high levels of spherical aberration the Sigma lens exhibits (confirmed by LensTip). We briefly investigated how much better the Sigma could do when working around its focus shift problem by comparing shots focused wide open vs. stopped down at 24mm, below.
Focusing wide-open vs. focusing at shooting aperture
As you can see from the widget above, the Sigma 12-24mm had to be focused at the selected aperture in order to get maximum sharpness at the focused (central) point. However, maximizing center sharpness ended up. In other words, it was difficult to optimize for both and sharpness with this lens.
It’s not the first time we’re seeing this sort of behavior (the venerable Nikon 14-24mm F2.8 exhibited similar issues); however, it’s fairly disappointing to a Canon shooter since all Canon DSLRs focus wide open, even in live view (or MF in live view). A workaround is to switch into video mode to focus, since this mode stops down the aperture. If you’re a Sony a7R II shooter you can get around this by using an electronic lens adapter (such as the Metabones Smart Adapter) that allows you to manually (or auto) focus at the shooting aperture.
The Canon lens, simply put, didn’t experience these types of issues as evident in the real world comparison widget seen at the top of this page. It was able to produce images with excellent sharpness, even when focused wide-open.
Sunstar and Lens Flare
|Sigma 12-24mm F4 Sunstar
Canon 5DSR, 16mm, 1/250, F18, ISO 100
|Canon 11-24mm F4L Sunstar
Canon 5DSR, 16mm, 1/320, F18, ISO 100
Both the Sigma and the Canon exhibit very aesthetically pleasing sunstars. Subjectively, the Sigma lens was able to achieve more obvious sunstars by an aperture of around F10, while the Canon had to be stopped down further (F14-F16). That gives the Sigma a bit of an edge: getting sunstars at smaller F numbers helps limit the effects of diffraction. That said, once the Canon was stopped down to F16 or F22, its sunstars offered ‘rays’ that are finer and more defined in shape, as opposed to the broader rays of the Sigma. The sunstars on both lenses are very symmetrical.
Lens flare is handled fairly well by both lenses and neither exhibit extremely strong or displeasing flare, which is quite the accomplishment for a lens with this large of a front element.
Unfortunately, the central sharpness in the Sigma suffers a great deal at and beyond 20mm. This is compounded by the fact that the best performance in terms of sharpness is only attainable by focusing at the shooting aperture instead of focusing wide open, as most cameras would traditionally do. Even this method of focusing won’t yield perfect results. Center sharpness sees a dramatic improvement while corner sharpness suffers. Manual focus also won’t help with this issue as focusing is done with the lens aperture wide open on Canon DSLRs (the only workaround is to focus in movie live view mode). The Sigma 12-24mm F4 offers some very nice optical performance at the short end of its focal range and excellent AF performance as well. The lens features an ‘HSM’ Ultrasonic focusing motor that offers extremely quiet and accurate focusing with speeds that closely match the Canon 11-24mm F4L lens.
|The Seattle skyline seen at sunset, shot with the Sigma 12-24mm F4 and edited to taste in ACR. Photo by Chris Williams
12mm, 1/60, F11, ISO 100
It is worth noting that at 12mm the Sigma performs exceptionally well in terms of sharpness, nearly matching the performance of the Canon lens across much of the frame, albeit never matching its central sharpness. This performance is maintained up until a focal length of about 18mm. Beyond 18mm the performance starts to really fall off due to the effects described in the text above, requiring you to focus and shoot at F8. Throughout the focal range the Sigma does a much better job with respect to the handling of distortion, lateral chromatic aberration and vignetting when compared to the Canon lens. Compared to the first, variable aperture version of the 12-24mm Sigma lens, this iteration is an improvement for Sigma, although not as great of one as we had hoped.
Given the high bar set by Sigma’s Art lenses, when I first heard about Sigma releasing this lens at a fairly affordable price I was extremely excited. Unfortunately though, the lens fell short in several aspects. The fact that longer focal lengths require you to focus at the shooting aperture to obtain the sharpest images possible is extremely frustrating, even more so because this comes at a cost to corner sharpness. The lens does have some very nice attributes including its handling of flare, vignetting, CA, distortion and its impressive sharpness across the frame at 12mm, but much of that becomes a minor footnote when looking at the lens sharpness, especially beyond 20mm.
For my money I would choose the Canon 11-24mm F4L over the Sigma. It really is one of the sharpest wide-angle zooms that I’ve ever had the opportunity to shoot with, plus it’s fully weather sealed. The lens’ short comings with respect to CA, vignetting and distortion are all largely correctable through the use of your favorite post processing software, so they don’t really impact the final image quality all that much. In short, I really wanted to love the Sigma, but the Canon just flat outperformed Sigma across the focal range, which makes it worth the extra money in my opinion. That said, if you’re only interested in the wider focal lengths, the Sigma is a formidable option at nearly half the price of the Canon.
The Sigma is a bargain for the image quality at the wide end, and its handling of chromatic aberration, vignetting and distortion. However, given the drop in performance on the longer end and the cumbersome workaround of focusing stopped down, it falls short of our top award.
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