Review – Sigma 24-105mm f/4 DG OS

Review – Sigma 24-105 f/4 DG OS
By: Justin VanLeeuwen | Twitter
Discuss the Sigma 24-105mm f/4 DG OS

Sigma is killing the competition.

Last year Sigma stepped up their lens game by restructuring their approach to lens production and design. Through the “Art,” “Contemporary,” and “Sport,” lines they promised to rein in their previously haphazard quality control and produce third party lenses that would be more than just the second choice for budget minded consumers. With the Sigma 35mm f/1.4 DG HSM, they proved that they were up for playing and beating Canon at its own game of high-quality glass. No longer just about filling in niche focal ranges, Sigma’s goal is to not just meet, but surpass Canon’s own lineup of popular high quality L-lenses.

Sigma 24-105mm f/4 OS

Sigma 24-105mm f/4 OS

In strong competition for Canon’s “most used standard zoom” the Canon 24-105 f/4 L IS has been a part of everyone’s full-frame kit as far back as I can remember. “White box” versions can be purchased on the cheap on eBay and the lens is often available for well below SRP anytime of the year. Canon’s lens is light, versatile, and accessible,but it’s notoriously soft at the corners and is fairly old in the lineup. Sigma’s has targeted this exact lens, creating a 24-105 f/4 DG OS to kill the competition.

(Full Disclosure: Gentec International (Sigma’s distributor in Canada) sent us this lens for use. It was a factory sealed retail version, with no restrictions in place to influence this review. My opinions are my own.)

Build
It’s not often that a tool like a lens gets so many comments on its industrial design. Sigma’s attention to detail on their art lineup goes well beyond Canon’s red-ring & composite metal construction on high-end glass. Sigma makes the lens itself a thing to appreciate. Sleek and curvy machined aluminum gives way to ridged rubber finger holds for focus and zooming. The textures beg for you to run your fingers along the contours as you lift the lens into your hands. A firm forward zoom ring will extend the lens through the zoom range until it rests, fully erect, at 105mm; 4.5cm longer than before.

The weight was the first thing I noticed when I picked up the Sigma 24-105. There is clearly a lot of metal parts in the build, setting it up at 885grams, as opposed to Canon’s 670, making it closer to Canon’s 24-70 f/2.8 L II at 805g. It is distinctly hefty.  The front lens element comes in at an 82mm filter size; I’ve said it before, but get used to it, 82 is the new 77. While a formidable zoom for its relative size, I don’t see the weight as a major detractor; after all, we often beg for this level of quality in so much of what we buy. It does feel well balanced on my 5D MKIII with added grip.

Canon EOS 5D Mark III | Sigma 24-105 f/4 , ISO250 1/200th f/8.0 at 80mm

Canon EOS 5D Mark III | Sigma 24-105 f/4 , ISO250 1/200th f/8.0 at 80mm

You’ll also soon notice how thin the focus ring is on the Sigma; it measures a mere 1.2cm. I was surprised to find how good it felt and didn’t really “miss” the larger focus rings of some of my other lenses. Perhaps it has to do with me heavily relying on auto-focus so often, particularly with zoom lenses like this. The Sigma 24-105 f/4′s zoom and focus rings are reversed from Canon’s in that the zoom is forward and the focus is rear on the Sigma. It’s not something I find altogether confusing, but some people may be used to the “Canon way” by now.

Your standard AF/MF and OS ON/OFF switches are lovingly inlayed on the side of the lens. They click firmly into place and I highly doubt you’d be able to accidentally actuate either of them.

I like Sigma’s center pinch lens caps more than Canon’s. They have a bit more grip to them though I have missed locking it into place on occasion. All Sigma lenses come with a padded soft case as well as a petal-shaped lens hood. The hoods have a ring of rubber near the rear to help grip them during removal, though I found myself leaving this hood on and ready to use at all times.

Image Quality
I don’t think Canon’s 24-105 was ever particularly well regarded for its overall image quality. It was a “get the job done” kind of lens; it served its purpose, and still better than most. I never added it to my own kit, opting for the Canon 24-70 f/2.8 L instead, but I do remember that its compromise in image quality and aperture were just enough for me to pass on it. Because I never used it and that the Sigma 24-105 is a direct focal-range match for it, I did some image test samples to try and judge just how one compares to the other.

Lucky for you, I have a really messy bookshelf that has lots of detail we can scrutinize. My method for these test shots was pretty straightforward: I shot on a tripod in in mirror lock-up mode, manually exposing the shots and using the center focus dot on the matrix to lock focus (neither the Sigma or the Canon stay consistently focused through the zoom range, I also could have manually focused, but for our purposes the results were good enough), and Image stabilization (IS) and Optical Stabilization (OS) were turned off on both lenses. Also note that this level of testing is not something I normally do and you can find other reviews with much more scientific methods and super cool sharpness charts that you can look at all day elsewhere.

Most zoom lenses are going to show their flaws at their extremes: wide open at either of the two ends of the focal length, either 24mm or 105mm. I also took some samples at approximately 50mm for posterity.

 

Canon EF 24-105 f/4L IS | Click for full resolution

Canon EF 24-105 f/4L IS | Click for full resolution

Sigma 24-105 f/4 OS | Click for full resolution

Sigma 24-105 f/4 OS | Click for full resolution

The most obvious result is that the Sigma lens performs better wide-open at the edges. The letters on the books are more legible and the cyan colour cast is better controlled. Purple fringing seems about the same to me and vignetting is slightly less on the Sigma. At 24mm, both lenses distort the image to the same extent. At 105mm f/4, I saw similar results, though it looks like the Sigma retains a bit more contrast and sharpness in the edges.

Sigma-vs-canon

Sigma 24-105mm f/4 OS vs Canon EF 24-105 f/4L IS

Looking at (approximately) 50mm, I noticed the Canon was quite soft, even stopped down to 8. The Sigma did not exhibit this at all and was sharp to my eyes all the way through the focal range.

Both lenses improved at the edges when stopped down to f/5.6 and f/8. I found chromatic aberration still present at the edges in both lenses, presented slightly different between the two makes, but not one noticeably better.  The definitive take-away, for me, was that Sigma greatly improved on the corners across the focal range as well as mid focal range sharpness and contrast over Canon’s older 24-105 f/4 L IS.

Sigma 24-105mm f/4 OS Vignetting Example

Sigma 24-105mm f/4 OS Vignetting Example

Optical Stabilization is to Sigma what “Image Stabilization” is to Canon: same thing, different name. Sigma, however, doesn’t provide a stop-equivalent number to accompany their OS. Like, for example, claiming you can shoot at 105mm at 1/30th of a second to achieve sharp images. While this may be true, I think it’s a safer marketing approach to an uncontrollable variable like your cameras motion vs. shutter speed. Through my own testing, I found that, with good technique (arms tucked in and locked, deep breath), I was able to shoot at 105mm and 1/8th of a second, a full four stops from a “recommended” 1/125th for the focal length. Of course OS only counters camera shake and is not capable of stopping subject motion.

I was impressed with how silent the OS was on this lens. I had to double-check it a few times to even see if it was running. In fact, apparently, OS is always activated on this lens, something that differs greatly from Canon lenses, which only activates IS when focusing and tracking.

Canon EOS 5D Mark III | Sigma 24-105 f/4 OS ISO 500, 1/80th f/7.1 at 74mm

Canon EOS 5D Mark III | Sigma 24-105 f/4 OS ISO 500, 1/80th f/7.1 at 74mm

I also found auto-focus to be silent, accurate, and slow. On my 5D3 in well lit sitiutions everything behaved as it should, but in darker environments where there was little to no contrast the lens truly struggled, as many would.

Who’s it for?
I’d be prone to say this lens is for “everyone.” Why not? It’s an incredibly versatile zoom covering a very popular focal range. It has more reach than the standard 24-70 with the benefits of OS and killer image quality to boot. But, where the Canon 24-105 f/4 L IS is an ideal travel lens, the added weight the Sigma brings makes this less practical for carrying around all day. The loss of a stop of light at f/4 also makes it fairly impractical for photojournalists and wedding photographers who shoot in dim-to-no light situations.

The Sigma 24-105 f/4 is an ideal studio lens. Beautiful and capable, it would work great in an indoor environment where a photographer’s shutter speed may be limited by their strobes, but sharpness and image quality are a priority. It could also travel well to locations and allow someone to shoot freely without changing lenses, as long as their needs don’t require an incredibly shallow depth of field. I could easily see this lens working for editorial shoots as that’s what I mainly used it for during my test period. I could switch from 24mm environmental portraits to fairly tight 105mm headshots without pausing to change my lens. This is especially true to those using crop-sensor cameras as it would bring you a portrait-friendly 38.4mm-168mm equivalent.

Canon EOS 5D Mark III | ISO 400 1/80th f/5.6 at 46mm

Canon EOS 5D Mark III | ISO 400 1/80th f/5.6 at 46mm

Nature and wildlife photographers may be better served by looking at the impressively light Canon 24-70mm f/4 L IS if they wanted a similar focal-range in their bag. Of course, if image quality at f/4 is your priority, it’s hard to beat the Sigma. In the end, how much weight you’re able to carry is a personal matter and a variable you weigh (pun!) against image quality, ergonomics and space in your bag.

Conclusion
My opening line said it all: Sigma is absolutely killing it with these new lenses. They perform, look and are priced better than the Canon equivalents. There are always going to be some trade-offs, like potential lack of third party incompatibility issues with future cameras. Sigma reverse engineers their lens mounts, so there’s the chance of a current Sigma lens not working with a future Canon body. However, Sigma Canada also offers a 7 year warranty as well as their user friendly USB dock to update lens firmware at home to address this issue. Their attention to industrial design and optics makes me think more of the even higher-end Zeiss lenses than it does a Canon, which is smart, because the cost difference between a Zeiss lens and Sigma is even greater, creating an even more compelling price gap in Sigma’s favour.

Canon EOS 5D Mark III | Sigma 24-105 f/4 OS, ISO 400 1/125th f/6.3 at 28mm

Canon EOS 5D Mark III | Sigma 24-105 f/4 OS, ISO 400 1/125th f/6.3 at 28mm

I do have a lingering question for Sigma: Why does this lens fall under your “Art” designation? I’d assume a 24-105 would fall under the C “Contemporary” lineup, but perhaps “A” is the new “L.”

As for the Sigma 24-105 f/4 OS it is simply the prettiest most capable 24-105 on the market. If it had a wider aperture it would probably give the Canon 24-70 f/2.8 L a run for its money and that is the best standard zoom lens I’ve ever used. As for the availability of the Canon for less? Skip it, the Sigma is worth the extra money and it’ll look better on your camera too.

Pros

  • Pretty, oh so pretty
  • Very sharp for a zoom
  • Optical Stabilization
  • Well controlled vignetting (less than the Canon)

 

Cons

  • Weight
  • Potential future compatibility issues