Fstoppers Reviews the Sigma 24-35mm f/2

The world's fastest zoom lens for 35mm full frame cameras is the Sigma 24-35mm f/2, and it's one way to follow up from making the world's fastest zoom for APS-C. Sigma has been making hit after hit for a few years now, leaving their "budget" lens brand stigma in the dust behind them. Having a 24-35mm may seem like an odd focal-length range that wouldn't be too useful, but I have found it to be an excellent range for a lot of the work I do in editorial and family portraiture. Let's start with just how it fits in my camera bag.

Versatility

This is perhaps the one area that might keep folks away from this lens. It doesn't have the convenience of a 24-70mm f/2.8, and it's not as fast as a 24mm f/1.4 or 35mm f/1.4. So where does it fit? Well, it's basically a bag of wide primes.

For me, the answer came when using my Fuji kit. I was constantly switching between the 16mm f/1.4 (24mm) and 23mm f/1.4 (35mm). It came to the point where you'd see me with one body slung over each shoulder, one with each of these lenses. I started looking into a 24mm for my Nikon system (I already had Sigma's 35mm f/1.4), and the memory of that juggle sent a shiver down my spine. It was around about that time that the rumors of this f/2 zoom from Sigma were coming to a close and the lens was to be released. I bought it a few months later, and haven't looked back.

In my shooting, I often find myself in very small rooms with families, or moving through crowds needing to change focal lengths quickly. The 24-35mm is perfect for this. Going just a touch wider or a little tighter when needed is easy. The wide f/2 aperture gives me plenty of light when shooting indoors or at night. These are the practical advantages, but the artistic one is by far more interesting.

The difference in the way lines and distance behave at 24mm and 35mm is very different. When you have space and time, playing with this can yield great results. If you remember my article about choosing your next lens, you'll recall that the wider a lens gets, the more perspective is distorted compared to what we see with our eyes. A 24mm lens will make lines converge and increase the perceived distance between foreground and background a lot more than a 35mm lens.

Now, one could argue that a zoom such as the 24-70 can also do this, and one would be correct. So, what's the benefit of this lens? The aperture and the sharpness. If you need the extra light, or to be super sharp wide open, the Sigma is a great choice. If you need the longer focal lengths as well, maybe a 24-70mm or 24-105mm is a better choice.

Size, Weight, and Build

As a user of primes almost exclusively, this is an extremely big and heavy lens for me. Those of you used to hoisting up a 24-70 or 70-200 should have no problems at all, but for me, it took some getting used to. The lens weighs in at around 940 grams depending on the mount, and is everything that the new Sigma lenses are famed for in terms of construction. We all know that these lenses are well built, and the 25-35mm is no exception to the rule. Its beautiful "thermally stable composite" construction, large focusing ring, and strong plastic hood leave nothing to be desired. It is slightly longer than Canon's 24-70mm f/2.8, slightly shorter than Nikon's, and has a massive 82mm filter thread.

Focusing and Sharpness

When I took the 24-35 out of the box for the first time, focusing was a disaster on my D750. I had guessed that it would be, because the 35mm f/1.4 I had bought a couple of years ago had been the same way. I had taken that lens into Sigma and had them calibrate it to my cameras for me, but this time around they were offering a free USB Dock with the purchase of any of their Art series lenses.

A quick aside about that dock. It's fantastic. Being able to calibrate a zoom lens like this at each of the four marked zoom points on the lens is a game changer. Playing with the in-camera fine tuning would mean making an overall change to the way the camera and lens work together. But what if it's good at 24mm, but way off at 35mm like mine was? That means by fine tuning to the 35mm end of the lens, I'd be losing the perfect focus at the 24mm end. About 30 minutes of comparing live view focus to the camera's AF system, and I was away to the races.

This lens is tack sharp. I'm not here to tell you that it's better, worse, or equal to the razor-sharp 35mm f/1.4 Art. That's for the guys who shoot test charts to do. What I will tell you is that, practically, there is no visible difference. The 24-35mm is adequately sharp wide open (at least in the center, see below) and only gets better as you stop it down. The edges are a different story, though. It's not until f/4 that I feel confident having my subject stray from the center while maintaining sharpness, especially at 24mm.

Center sharpness f/2 vs f/4 at 24mm

Center sharpness f/2 vs f/4 at 35mm

Corner sharpness f/2 vs f/4 at 24mm

Corner sharpness f/2 vs f/4 at 35mm

Optical Qualities

Bokeh is decent for a wide angle, and it falls off nicely from the in-focus parts of the image. Even at 24mm, f/2 allows you some good separation between your subject and the background.

Flare is well controlled, but not as well as the 35mm f/1.4. For this, I am so thankful. I love a bit of flare. I love the loss of contrast it brings, and the fluffy soft feeling around a light source in the image. I struggled so hard to make the 35mm render like this, but it's just so well corrected that it's almost impossible. But, with the 24-35mm, I'm finally able to get some degradation when I point the lens at a light source. Some might call this a defect, I'm certainly happy to have it!

That vignette, though. At f/2, you loose almost two stops of light in the corners. Check the before and after below for an example. Although this can be corrected for in post, it's significant enough that in dark situations, you'll lose detail in those areas completely. Stopping down helps, and even by f/2.8 it's significantly better. However, it never really goes away completely.

Andy from Andrew Faulk Photography and his family at f/2, before and after lens corrections.

What I Liked

• The focal length range
• Sharp wide open
• Fast, silent focusing
• Flare!
• Sigma Dock

What I Didn't Like

• Size and weight
• The excessive vignette

In Conclusion

If you like these focal lengths, this glass is a no-brainer. It's sharp, fast, and versatile. I've been using it for everything from family portraits to editorial work and corporate events. It hasn't let me down so far. Do get the Sigma dock though. You'll only use it once for each camera, but it's worth it for the detailed fine tuning you're able to make.