The Sigma 105mm F1.4 DG HSM Art debuted earlier in the year (2018), around May, and is around $1400/Â£1500. From the DG designation you can tell that it’s a full-frame lens and it’s available in Canon, Nikon and Sigma mounts. It is of course targeting the recently introduced Nikon AF-S Nikkor 105mm F1.4E ED, but would also appeal to Canon users, where a high-speed L-series model is not currently offered in that focal length.
It may also be possible that it becomes available in Sony FE mount; it is already suitable for mirrorless cameras. Sigma, like other independents, design their lenses to accommodate the mount with the longest flange-back distance or register first, which is the most challenging. That’s currently the Nikon F mount *. Once this is achieved, it’s relatively straightforward to accommodate other mounts with shorter registers. For this reason, Nikon mount lenses were usually available before Canon, with others following afterwards. Sigma has recently introduced some Art series in Sony FE mount, that effectively have an ‘extended’ barrel to accommodate the additional flange-back distance of the missing mirror. Update: According to Sigma, this lens will be available with the Sony FE mount in October.
Regardless of camera type, at around 1.4 kilos this is a big and heavy lens and should never be held by the camera body alone for fear of stressing the camera’s mount. It comes supplied with a detachable tripod collar with (Nikon and others please take note) an Arca-Swiss type groove milled into the foot. It’s solidly made and rigid and has a pin in the rear to attach the included should strap. It’s just as well that it is detachable, as although large, this lens is actually short and stubby. You could rotate it 180 degrees as you would with much bigger lenses to use as a handle but it’s bit short. Besides, it adds to the weight, so for hand-held use it’s better removed. With the tripod collar and foot detached, Sigma thoughtfully provide a synthetic rubber ring to cover the locking screws that protrude from the barrel – a nice touch!
Like all of the Art series, Sigma has adopted a combination of metal and composite material for the barrel. And it has those familiar sober details, such as a small AF window, and toned-down distance scales which are difficult to see in low-light. Nevertheless, the build is comparable to rivals, and perhaps even superior to some. And, that certainly applies to accessories such as the padded case and dedicated carbon-fiber reinforced plastic hood, which is not only ridged internally and has rubber ‘bumper’, but is not too tightly fitting like some I could mention.
Auto-focus is a highlight, like it is with most if not all modern Sigma lenses, certainly those bearing the HSM moniker. Whether it’s a ring-type sonic motor, like those used in Canon L-series lenses is hard to say – focusing is fast given the size but Sigma don’t disclose such things. Nikon use both ring-type and micro-type sonic motors with gears under their SWM moniker, which accounts for the 105mm F1.4 E slightly shrill sounding focusing. With near silent operation not to mention the size and weight of the Sigma suggests a powerful, more expensive ring-type motor but even then the Sigma isn’t noticeably faster in focusing. Manual focus isn’t too highly geared either. Even so, it’s still quite easy to move in and out of the plane of focus wide open in the viewfinder which has an apparent depth of field of F2.8-4, let alone when using magnified live view. Needless to say, when focusing on an eye, or rather an iris, when taking a portrait it’s easier and more reliable to use AF.
So how about the image quality, does it match the Nikon equivalent? In terms of resolution, maybe. The Sigma is sharper wide open and increases slightly in the outer zones on stopping down. But there’s more to IQ than that. This lens isn’t called the “bokeh master” for no reason; it has very smooth transitions to out of focus detail with only a hint of the double-edged effect or lining on specular highlights from slight over-correction of spherical aberration. But most impressive of all is that there’s practically none of that difficult to remove axial fringing and spherochromatism, something that can’t be said of the Nikon equivalent. Without doubt, it’s a superb performer with exceptionally pleasing drawing style, but even that isn’t as well-corrected as the Sigma. Admittedly, the Sigma has very attractive if slightly warm rendering, and despite the size there’s some vignetting wide-open. As for flare, it’s not so much if the coatings resists it or not, it is how they handle it that matters; contrast falls of course but ghosting is exceptionally well controlled.
If you’re looking for a ultra-fast 105mm and a Canon or Nikon user then the Sigma is undoubtedly very tempting. Canon users don’t have an alternative; there’s nothing really like it unless you prefer shorter or longer focal lengths. You could perhaps go for the Canon EF 100mm F2.8L Macro which is a great performer and arguably more versatile even for portraiture. Otherwise, it’s choice between the excellent Canon EF 85mm F1.4L USMor aging but still superb Canon EF 135mm F2.0L USM. Nikon owners likely will lust after the Nikon Nikkor AF-S 105mm F1.4E ED, but it’s an expensive lens by any standards even if it’s smaller and lighter. It’s still not cheap, but the Sigma is the better performer between them; just be prepared to make extra room in your kit bag.
* Nikon will have had many reasons for this, as it’s challenging, however I presume the most persuasive argument at the time was to allow for a large mirror – and prevent so called “mirror cut-off”, where part of the image is cropped in the viewfinder. In some rivals this occurred when using focal lengths of 500-600mm and longer, though pro-level Nikons could be used with an 800mm lens with no ill-effect.
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