It used to be a joke that the pronunciation of "Sigma" was with a silent "t."
Those days are gone.
Though there are lingering vestiges of the brand as we knew it, it's no longer the case that the value of a Sigma lens was that it is more or less as good as the OEM lenses for less money. It's now more true to say that the best Sigma lenses are equal or better than their Canon/Nikon/Pentax counterparts, and they cost less. This is certainly true of the 35mm f/1.4 DG HSM. For some, the price difference to the other f/1.4 35mm primes would be enough to change sway their purchasing decision, but brand loyalty is not built on price competitiveness alone. As is often the case, lasting brand growth is product lead and not sales driven. For Sigma, it would appear to be a strategy of cultivating photographers who love not only the lower prices, but the lenses themselves. That seems be the case with the 35mm.
Build and Design
The construction of this lens is archetypical of the refreshed Global Vision line-up. It's shed the drab matte appearance of the previous generation and embraced a new upscale aesthetic. The colour of the material is not quite black, but it has a deepness to it that makes it appear more than just a simple deep grey.... there's depth to how the light falls off of it that gives the plastic body a bit of an obsidian-like glassy sheen. Tolerances are tight and there isn't a trace of wobble anywhere in the lens. The focus ring turns with a smooth damped feeling that is in keeping with the best lenses out there. Focus operation is quick and silent thanks to the HSM mechanics, with no signs of AF hunting or hesitancy in moderately indoor light situations.
Like all of the Global Vision lenses, this is not merely made with a conventional plastic,and instead uses a type of composite material that Sigma has branded TSC(TM), for "Thermally Stable Composite." This is a polycarbonate-based composite. The key benefit of the material appears to be that it has similar thermal expansion properties as metal, meaning that the lens as a whole can be built to smaller tolerances. The interfaces between the plastic parts of the lens and the metal parts can be made smaller, thus reducing size and weight. That said, this is neither a light nor a small lens. It will be at home on a Canon 5D Mark III or a D800, but it will feel distinctly front heavy on a smaller camera like the D7100 or the EOS 70D.
|Sigma 35mm f/1.4 on Nikon D800|
Paradoxically, the size and weight of the lens work at cross-purposes to what a 35mm prime is supposed to do. Classically, the 35mm (film) equivalent field of view is the go-anywhere, shoot in any situation setup for what is commonly known as street shooting. However, unlike the Leica M cameras that typify this approach, any full frame camera with the Sigma 35mm f/1.4 will be ostentatious and heavy.
All of the qualities that you would expect from a high-grade OEM lens... high resolution, low distortion, smooth out-of-focus rendition... are apparent in the images that the Sigma 35mm is capable of producing. On a crop sensor camera and used as a "normal" prime, this lens is overkill:
|f/1.4 on Canon 70D|
|f/1.4 on Canon 5D Mark III|
The same virtues that were seen on the crop-frame shot are also evident on the full frame image. There's more vignetting present, but no more than what would be typical for most fast prime lenses. Barrel distortion is also very low across the frame of the picture. In controlled objective testing, the Sigma displays some field curvature when used wide open, but it's nowhere near as bad as the equivalent Canon EF 35mm f/1.4L USM and it's fairly close, if not slightly sharper than with the Nikon AF-S 35mm f/1.4G.
Below is the progression of the lens from f/1.4 to f/11 on the Nikon D800. This is an ad hoc test to illustrate what the subjective quality of the bokeh looks like when the lens is focused on an object at short distance - approximately five feet from the camera. The smoothness of the bokeh is partly down to the use of a curved nine-bladed aperture; note the roundness of the pinpoint highlights in the f/1.4 sample.
This is a good lens, but is it a good lens for it's application? That's a harder question to ask. For street shooting the problem is that the Sigma mated to a full frame camera becomes a heavy piece of equipment.... not unwieldy, but certainly less discrete than using other possibilities, such as a mirrorless camera or a rangefinder. However, it can't be understated how how well the Sigma 35mm fulfills its commercial purpose by the virtue of it's competence and price competitiveness. Given that the chances are fairly high that owners of the Canon 5D Mark III or Nikon D800 will be using their respectively excellent 24-70 f/2.8 zooms, any prime that falls within this focal length range would have to be something special to warrant use over the more convenient zooms. The Sigma 35mm fulfills this requirement: it's a lens that you'll want to use wide open all the time.
Compared to Canon and Nikon's 35mm f/1.4 lenses, the value proposition is clear. The Sigma costs less and is just as good. However, the Sigma sits between those top tier lenses and Canon/Nikon's entry level primes, the Nikon AF-S 35mm F1.8G ED and the Canon EF 35mm f/2 USM IS. The Sigma is heavier, more expensive and sharper than these two lenses, and of course... it opens up one more stop to f/1.4. These lenses aren't directly comparable, but since the Sigma is only a few hundred dollars more, it's the "aspirational" option. If you are shopping for a lens of this type, the Canon and the Nikon are the logical value-oriented choices whereas the Sigma is the one that makes you save a bit more to reach up to a higher-grade lens. It's not an insignificant amount of money, but it's less of a reach than to the OEM f/1.4 lenses.
The global camera market is forecasted to contract in 2014 but product-wise, Sigma is well positioned to deal with the changing landscape. In a shrinking market, the natural tendency is for companies to head towards the high end where margins are wider than with the low-margin high-volume value end of the market. With lenses like the 35mm f/1.4, Sigma will not only be able to last through the current camera recession, but will be in a better position for the (eventual?/possible?) upturn in the camera market than if they had stayed purely as a value-oriented brand.
With thanks to Broadway Camera