There's been a great deal of interest in the Sigma 24-35mm F2 Art since its launch last month. And who can blame the internet for getting excited over the world's fastest full-frame zoom? It has the potential to take the place of 24mm, 28mm and 35mm primes in a photographer's bag, which are particularly popular with wedding photographers and photojournalists, as well as those interested in environmental portraiture, night-time landscapes, and more.

With all of the appeal and high-end touches offered by Sigma's 'Art' series, the 24-35mm just begs to be taken out for a spin - and DPReview's Deputy Editor Rishi Sanyal did just that this past weekend. Take a look at his shots, including aperture progressions at both ends of the zoom, at the eye-popping resolutions a 5DS R provides with this groundbreaking zoom. And have a look below the break for some notes on nuances I experienced when shooting with this particular combo, as well as answers to some frequent questions our readers asked upon viewing this gallery.

Shooting with the Sigma 24-35mm F2 on a Canon 5DS R

Focus in Live View

While our initial tests show the lens' focus motor is very accurate and fast, in order to guarantee focus many of these shots were focused in live view. This simply reflects a limitation of phase-detect AF (PDAF) modules in DSLRs shot with such fast lenses with shallow depth-of-field. For example, small differences in mount thicknesses between your camera body and the next can throw off the accuracy of lenses, as can residual spherical aberration, skew or imperfect placement of the PDAF module, and more. Things can get even worse with off-center AF points. The sum total of these issues essentially means calibration is often required for lenses where focus is critical, and Sigma thankfully provides this ability with all their Art lenses via a USB dock. Most camera manufacturers also allows for such calibration, and so Sigma's offering of a dock is in no way an admission of a shortcoming of their lenses and, in fact, quite the opposite: Sigma's utility is the most comprehensive, offering optimization at four different focal lengths, and four different subject distances.  

Still, to guarantee focus, you'll fare better in Live View, which uses highly accurate (but slow) contrast-detect AF. By the way, these inaccuracies are not something mirrorless cameras with on-sensor PDAF struggle with, since their focus measurements are always made on-sensor using the same light rays that will form your image.

I focused on eyes in Live View to guarantee focus, given the inherent inaccuracies of phase-detect AF modules in DSLRs. Not to mention, additionally used shutter speeds that would avoid all types of mirror and/or shutter-induced shock (thankfully, the 5DS R offers an electronic first curtain when shooting in Live View). That said, operating a DSLR in Live View is, well, kind of against the point of a DSLR, and I was constantly reminded of this by the cumbersome Live View shooting experience.

It's worth noting though that shooting in Live View slowed down the shooting experience tremendously, relative to what you'd expect with a DSLR. This made it significantly harder, if not impossible, to capture candid in-the-moment shots. If I weren't shooting to produce a gallery of images that'd no doubt be pixel-peeped, I'd be OK microadjusting and just using traditional through-the-viewfinder shooting (although at 50MP, any focus inaccuracies are quite obvious). However, shooting in Live View to guarantee focus accuracy I couldn't help but wonder if it would've been better to use a tool better designed from the ground up for Live View shooting. For example, the lack of an EVF meant I couldn't even check if my shots were in focus in the bright sunlight.

Would I have raised these concerns 5 years ago? Probably not. But given what top-of-the-line mirrorless are showing us these days, it's hard not to ponder these things.

Skin Tones in the Golden Hour

Many skin tones here are orange because I tend to shoot during the Golden hour (hours around sunrise and sunset), as those fleeting, ephemeral moments are what I love to immortalize in captures. As such, skin tones in these shots tend to reflect the intense orange of these sunsets (and these were some of the reddest sunsets I've seen in some time). I decided to leave the cast of the sunlight in the images, to evoke the feeling of the light on their faces I got when I experienced everything in person. And particularly because I tend to like the way Canon renders reds and oranges, I prefer to leave them as they appear in the default 'Camera Standard' rendering.

The Golden hour gives very orange tones to our subjects, especially with the particularly red-shifted sunsets we've had of late in Seattle. Canon's default conversions have no dearth of reds in them, and frankly I prefer the skin tones that result.

Dynamic Range

Wider focal lengths mean you have the opportunity to include a lot in your frame. And during the golden hour, that often means a lot of bright skies juxtaposed with subjects in deep shadows. Why do I mention this?

Some of our astute readers noticed that noise levels in shadows of some shots appeared to be higher than what one would expect at the stated ISO of the file (100 for the shot below, for example). This is simply due to the fact that midtones (such as the subjects' faces here) had to be raised from 'shadows' in the Raw file since a conventional underexposure was required to retain tones in the sky and around the sun in the high contrast scenes. The intent of many of my shots is to match closely what my eyes saw, which in the example below was the entire range of tones from my friends' faces to the clouds in the sky to the sun. To convey this in the photograph required me to expose for the highlights and then 'tonemap' the images (lift shadows) to display this large range of contrast in one photograph. This process of pushing shadows a few stops can expose shadow noise, particularly for cameras with less competitive dynamic range. Therefore, the noise you're seeing in midtones/shadows of some of these shots is the result of running up against the dynamic range limitations of the 5DS R.

The Golden hour also means lots of high contrast scenes, which means lots of dynamic range. To capture this range in, e.g. the shot above, I first exposed for the highlights (which only required dialing in 2/3 EV exposure compensation, as the camera's meter already underexposed the scene due to the bright sun), and then tonemapped the image by lifting shadows to make the subjects' faces visible. The somewhat limited dynamic range of the 5DS R, while significantly better than Canon's previous offerings, did mean some noise in darker tones even at ISO 100, evident in our subject's neck and t-shirt here.