<H1>Sigma 50mm f/1.4 Art Lens Reviewed</H1>

SLRGear and others recently tested the Sigma 50mm f/1.4 Art lens and raved about the results, as compared to the Canon, Nikon and Zeiss (55mm) 50mm lenses. It is important to point out the Sigma lens has 2014 technology. The Canon EF 50mm f/1.2L and EF 50mm f/1.4 were introduced in 2006 and 1993. When comparing lenses, it has to be apples to apples.

Everyone knows in the last few years, many new improvements have been made in coatings and optics. I do not doubt the new Sigma 50mm f/1.4 Art lens is very good and an excellent value for the money. Canon is expected to introduce a new EF 50mm f/1.4 some time this year. Once the latest 50mm lens from Canon and Nikon are released, they will at least match or surpass the Sigma Art lens' performance. As for the $4,000 Zeiss Otus 55mm f/1.4 lens. Any average person can deduce it will not take a photo 4 times 'better' than a $1,000 lens and is therefore a bad value for the money. The Sigma 50mm lens is listed as $949 in the U.S. and shipping starts at the end of April. I may give it a test once it is available.

MichaelDanielHo.com

Below is an excerpt from the SLRGear test results :

"When we sat down with Sigma at this year's CES, we got some hands-on time with the lens. The build quality was exceptional, but what really got our attention was Sigma's off-handed remark that they weren't looking to surpass Nikon and Canon, but rather the $4,000 Zeiss Otus 55mm f/1.4 monster.

The Sigma 50mm f/1.4 Art is quite large and bulky with a total of 13 elements in 8 groups, including 1 aspherical and 3 super low dispersion elements. Other optical performance features include a 9-bladed rounded aperture for pleasing and smooth background blur and Sigma's latest Super Multi-Layer Coating to reduce lens flare and ghosting. Focusing should also be fast and quiet thanks to their Hyper Sonic Motor AF system.

50mm is a classic focal length for the full-frame shooter, and after Sigma's astounding 18-35mm f/1.8 Art DC lens, it wouldn't be an exaggeration to say this is one of the most anticipated products of the year. The competition from Canon and Nikon includes garden-variety 50/1.4s on the low end, with Nikon offering the slightly longer 58mm f/1.4 Nikkor on the high end, and Canon the f/1.2 L.

The Sigma 50mm f/1.4 Art lens ships with front and rear caps, a bayonet-mounted lens hood and a sturdy soft case, and is set to be available in Canon, Nikon, Sony Alpha and Sigma mounts.

So how does the Sigma stack up? In a word, or three: very, very well. Read on to find out more...

Sharpness 

Since Sigma apparently developed this lens to compete with the incredibly sharp Zeiss Otus (a $4,000 55/1.4 optic), we've been expecting it to be pretty sharp. Interestingly, though, Sigma president Kazuto Yamaki told IR/SLRgear founder Dave Etchells that they actually traded off just a little sharpness, in order to achieve better local contrast.

While we haven't had a chance to test it against the Zeiss Otus yet (we'll update this if/when we do), comparing the Sigma 50mm f/1.4 Art lens against high-end competition from Canon, Nikon, and Sony, it certainly seems like Sigma succeeded in their goals. The lenses we're comparing with here are the Nikon 58mm f/1.4G AF-S Nikkor, the Canon 50mm f/1.2L USM, and the Sony FE 55mm f/1.8 ZA Carl Zeiss Sonnar T*.

The Sigma 50/1.4 Art's sharpness holds up very well against this competition. At f/1.4 and on a full-frame camera, it pretty well blows all of the others out of the water. The Canon 50/1.2L is pretty sharp in the center, but the corners are extremely soft. The Nikon 58/1.4 is less sharp in the center, and quite soft in other parts of the frame. The Sony 55/1.8 obviously doesn't get to f/1.4 at all, so there's nothing to discuss on that front.

The other lenses all improve at f/2, but so does the Sigma 50, easily bettering all the others, at every point across the frame. At f/2.8, the Sigma's blur characteristic is almost perfectly flat, and quite sharp everywhere. The Nikon 58/1.4 is quite sharp in the center, but still with softer corners, albeit not quite as bad. The Canon 50/1.2 is also quite sharp at the center, with a little corner softness, and the Sony 55/1.8 is fairly flat, but still a bit softer on the left and right sides. At smaller apertures, the Sigma stays very flat and very sharp, with just a hint of diffraction limiting creeping in at f/8, as is the case with the other three lenses as well. The Nikon 58/1.4 never really flattens out, all the way to f/16, while the Sony and Canon optics are both quite flat by f/8.

Sub-frame sharpness results are about what you'd expect, just crops of what we saw in the full-frame bodies. The Nikon improves more than the others, since its sharpness a ways out from the center is so much worse than areas near the center that a lot of the worst wide-open blur behavior just doesn't appear within the sub-frame sensor area.

(Ed. Note: Given the extent to which we expect people will be squinting over these results, it's worth noting here again that differences in sharpness associated with a single color level change really aren't discernible visually, no matter how much you might care to pixel-peep real-world images. So please, no angels-on-the-head-of-a-pin arguments over one lens or the other being one shade of pink/purple than the other here :-)

Chromatic Aberration 

CA is quite well controlled in the Sigma 50mm f/1.4 Art lens, with a very low average value at f/1.4 on a full-frame body, increasing gradually to a still-low value at f/2.8 and remaining constant as you stop down further. The maximum CA is a bit higher at f/1.4 and f/2, decreasing to about f/4. This difference between maximum and average CA means that the Sigma's CA is confined to a small portion of the frame, mainly in the corners. If there were any weak point in the Sigma's performance compared to the competition, it would probably be CA, as both the Nikon and Sony beat it on that score. The Canon 50/1.2 is higher in both maximum and average measures, though. On sub-frame bodies, the results are somewhat similar, although the Sigma's maximum value is lower wide open, and both max and average values are a little higher at f/2.8 and above. The Canon 50/1.2 shows considerably worse maximum CA on an APS-C frame. (It's quite common for lenses to show worse CA on smaller-frame bodies, since the CA is measured relative to frame height, and a given displacement between the colors will correspond to a larger percentage of the smaller frame size.)

Shading (''Vignetting'') 

Shading is very common on large-aperture lenses when shot wide open, so it's not surprising to see a fair bit of it in the Sigma 50/1.4 Art. That said, though, it handily beats both the Canon and Sony competitors in this area, and the Nikkor only just edges it at f/1.4. The Sigma easily beats even the Nikon by f/2, although interestingly, the Nikon shows less shading at f/2.8 and higher than any of the other models we're discussing here. That said, though, light falloff with the Sigma is less than a quarter of a stop at f/2.8 and higher on a full-frame body. On an APS-C body, the Sigma's maximum shading is just over a quarter of a stop, and less than a tenth of a stop at f/2 and above.

Distortion 

The Sigma 50mm f/1.4 Art lens easily carries the day here, with almost immeasurable geometric distortion. (Average distortion is pretty much dead-zero, max distortion shows the tiniest hint of pincushion.) On a full-frame body, the other three lenses all show some degree of barrel distortion, the Nikkor the most, at about 0.5% max and 0.2% average, the Canon next at perhaps 0.4% and 0.2% respectively. The Sony does the best of the other three, with maybe 0.2% max and under 0.1% average. On sub-frame bodies, the Sigma's distortion is also near zero (no surprise), and distortion of the Canon and Nikon are both reduced, but the other Sony's characteristics change a little. This is often the case with highly-corrected lenses like these, in that the distortion doesn't just rise continuously as you move out from the center. For instance, if you look closely, you might find a little barrel in the center, some pincushion a bit out from there, and barrel again in the corners - or some other combination, depending on the lens in question. In the case of the Sony 55/1.8, the maximum distortion is a slight pincushion effect, while the average is a slight barrel effect. Both are under 0.1%, though, so could be considered negligible. By any measure, though, and regardless of frame size, the Sigma 50mm f/1.4 Art's distortion performance is just phenomenal.

Focusing Operation 

The Sigma 50mm f/1.4 Art lens focuses quickly -- and practically silently -- thanks to its Hyper Sonic Motor electrical AF system. However, it doesn't feel like the fastest AF in the world when racking all the way from minimum to infinity focus, which takes around one second, or perhaps a hair longer. Focusing in everyday scenarios with subjects in the intermediate focus distances felt very fast and accurate, though, and at times nearly instantaneous.

Of course, there's manual focusing as well, plus full-time manual focus override when using autofocus. The focus ring rotates very smoothly with enough resistance to prevent accidental adjustments but easy enough to adjust with a thumb and forefinger. The ring has soft stops at both minimum and infinity focus distances and provides a little over 90 degrees of rotation.

Macro 

This lens isn't specifically built for macro shooting with a maximum magnification ratio of 0.18x (1:5.6) and a minimum close-focusing distance of around 40cm (1.3 ft.). Therefore it's not great for true macro shooting, but can still focus relatively close, making it great for up close portraits, products shots, etc.

Build Quality and Handling 

A lightweight "nifty fifty" this lens is not! The Sigma 50mm f/1.4 DG HSM "A" is a serious lens, with serious weight and build quality. Like the other Global Vision lenses before it, the new Sigma 50mm f/1.4 Art lens is very well built, making use of their Thermally Stable Composite material, that despite technically being a form of polycarbonate plastic, looks and feels more like metal (and shares similar thermal properties to aluminum, as well). The barrel design is finished in a smooth matte black texture, with a nice, thinly-ridged texture along the underside for some grip. The large 1.5-inch-wide focus ring has a similar ridged texture embossed into the thick, rubberized grip. If you've used any other Sigma Global Vision lenses, such as the 24-105mm f/4 or 35mm f/1.4, you'll be familiar and undoubtedly impressed with the design and build quality of this lens.

Other optical performance features include a 9-bladed rounded aperture for pleasing and smooth background blur and Sigma's Super Multi-Layer Coating to reduce lens flare and ghosting.

Being a prime lens, the lens is a pretty straightforward affair in terms of bells and whistles. A focus distance window complete with a distance scale and depth of field markings sits on top of the lens. There's also a MF/AF switch on the left side, which has a nice, solid feel to it -- no risk of accidentally toggling focus modes. The reversible polycarbonate lens hood feels very solid with a rubberized bayonet mount that snaps in place with satisfying click -- no issues with wiggle or play.

We mentioned "serious weight" and we're not kidding. This lens is large and bulky, with a total of 13 elements in 8 groups, including 1 aspherical and 3 super low dispersion elements, all inside a large diameter barrel that accepts 77mm filters. Unlike similar lenses from other manufacturers, such as the Nikon 58mm f/1.8G or Canon 50mm f/1.2, the Sigma 50mm f/1.4 Art is both longer and heavier, at just shy of four inches long and around 810g (28.6 oz.) in weight. On the other hand, unlike its intended competitor, the Zeiss Otus 55mm f/1.4, the Sigma is noticeably smaller and lighter. Nevertheless, this lens is definitely not a lightweight, go-anywhere lens like the typical 50mm f/1.4 lens.

Our full-frame test camera for Canon lenses is the 1Ds Mark III, which is far from a lightweight camera on its own. With the Sigma 50mm lens mounted to that camera, it's a heavy combo. Even on our smaller Canon 7D body, it makes for a pretty hefty pairing. However, if you're used to using large lenses and larger cameras, the weight and bulk of this lens is not overbearing or awkward. It actually feels more akin to using something like a 24-70mm f/2.8 lens (in fact, this Sigma 50mm is almost the same weight as the Canon EF 24-70mm f/2.8L II USM) and is nicely balanced on both the large, full-sized DSLRs as well as medium-sized ones.

Alternatives

On the Nikon side, you have basically three options :

The affordable 50mm models in f/1.4 and f/1.8 versions, available for around $450 and $220, respectively. That's a significant savings on the likely price of the Sigma. The image quality of these models, while far inferior to Sigma's triumph, aren't terrible, at least she stopped down - but stopped down isn't what the Sigma is all about.

The slightly longer 58mm f/1.4 Nikkor available for $1,700 Even though Nikon pushed the focal length on this one, results are only marginally improved from the $450 50mm f/1.4 mentioned above. We really can't recommend this lens over Sigma's 50mm f/1.4 Art.

On the Canon side, your options are similar :

Like Nikon, Canon offers lower-cost 50mm options in f/1.4 and f/1.8 variants, for about $400 and $100, respectively. These lenses will struggle wide open, but perform well when stopped down, though you'll again need to get to f/2.8 and f/4.0 before things become tack sharp.

On the high end, Canon offers a direct focal length-competitor in the $1,700 50mm f/1.2 L. While you gain a half-stop advantage, this lens is quite soft in the corners, even at f/1.4. Light falloff and CA are both factors that also put it solidly behind the Sigma. Here too, the advice is easy: buy the Sigma 50mm Art.

Carl Zeiss offers the $4,000 55mm f/1.4 Otus. This lens is a sharpness monster and, while we've yet to review it (coming soon), we're hard pressed to find a strong reason to recommend it, given Sigma's stellar performance for a (likely) price less than half that of the Otus.

Conclusion 

The Sigma 50mm f/1.4 Art is the most exciting lens we're likely to review this year. All competing lenses from Canon and Nikon fell short when compared to the resolving power of the 50mm Art. We haven't (yet) tested the very best from Zeiss, but we are confident Sigma will trounce it in one key area: price. This difference is likely to be a yawning chasm. Our expectation for pricing on this lens is for something at least a bit less than Canon's 50mm f/1.2 L, which goes for $1,700; despite a variety of rumors and no official price for the Sigma yet, we're expecting it'll be less than that.

Even if the price is 'merely' even with the best of Canon and Nikon, this lens is easy to recommend. Put simply: it trounces any similar model available for less than $4,000. If it comes in significantly cheaper than the best of Canon and Nikon, Sigma will have made a friend of every full-frame shooter in the land."