Quick take: After eight months of portraits, concerts, corporate gigs and rainy walkarounds, the Sigma 17-40mm F1.8 is my go-to lens on Fujifilm, and I think it's the best lens on the X-mount, period. It's wider, longer, lighter and weather sealed compared to the legendary 18-35mm, with an aperture ring, AFL buttons and an internal zoom. Autofocus performs like native Fuji glass, it's tack sharp wide open across the range, and at $919 it replaces about $3,200 worth of Fuji F1.4 primes.
The Sigma 18-35 Legacy
Before incremental release cycles and YouTube-fueled gear buying, the Sigma 18-35mm F1.8 carved out a category that didn't exist. It set a new standard for what an APS-C zoom could be, and it was affordable for solo shooters and productions of all sizes. It became the first real "bag of primes" zoom, giving crop-sensor shooters good low-light performance and that full-frame look in a lens that didn't cost more than their entire kit.
The Sigma 17-40: The Terminator 2 of APS-C Zooms
The 17-40mm isn't a Mark II. It's better in every way a lens can be better:
Wider at 17mm and longer at 40mm (about 25.5-60mm full-frame equivalent).
Lighter weight.
Weather sealing, the one thing people really wanted on the original.
Mirrorless-native perks like an aperture ring and two well-placed AFL buttons.
I bought this lens with my own money and waited for the new-gear excitement to wear off before reviewing it. Over eight months, it's been my lens for walkarounds, street photos, YouTube videos, portrait shoots, run-and-gun client gigs and plenty of shoots where the weather didn't care about my gear. Yes, I've used it in the pouring rain.
The Improvements
The lighter weight sounds minor, but it makes the lens balance much better on smaller Fujifilm bodies like the X-T5. It even works on the X-M5, though that's pushing it. For me, it feels most at home on the X-H2S with a battery grip. It's the perfect setup, even more than Fuji's own 16-55mm, which I previously thought was the best all-around lens on the system.
The AFL buttons let you lock focus without changing your grip, which is probably a bigger deal for video. The aperture ring has great feedback and can be de-clicked with a switch for smooth iris pulls, which tells me Sigma designed this with Fujifilm shooters in mind. The focus and zoom rings feel great too.
Like the original, it's an internal zoom. That makes rigging it on rails or a gimbal far easier than a lens with an extending barrel like the 16-55mm. I wouldn't be surprised to see it rehoused as a cine lens someday, like its predecessor.
Photo Autofocus
Because this is Fujifilm, autofocus is the big question. The short answer: it performs like native Fujifilm glass, and it'll only get better with firmware and new bodies (fingers crossed for an X-H3S).
On the portrait shoot you see in the video, I took a few hundred photos and fewer than five were out of focus. Those were mostly under tree leaves, where the camera mistook leaves for eyes. It was a purposely tough scenario that would challenge almost any camera. I also keep manual focus override on a custom button on every body, because autofocus is always guessing in complex scenes with strong foreground elements.
Overall, photo autofocus has been on par with the Canon R5 and R5 C I shoot with commercially. I even used it on my X-T3 for group photos at a private golf event, then carried it the rest of the day as my one wide-and-tight lens with a diffused on-camera flash.
Video Autofocus
Video shooters will be happy: the motors are fast and quiet, and it tracks subjects moving side to side and toward the camera, which is usually where things fall apart. Focus breathing is basically non-existent at 40mm and only slightly present at 17mm, which won't matter in real-world use.
Even on the X-T5, not Fuji's best autofocus body, it nailed shots of my buddy's band, Troubleman, in near-complete darkness with lasers cutting through the frame.
Image Quality and Performance
That 25.5-60mm equivalent range covers street, landscape and portraits with creamy, out-of-focus backgrounds, which is why it truly works as a bag of primes. I was surprised how often I used the 17mm end on portrait shoots, just because I could.
There's a little barrel distortion at 17mm, but you'll only notice it up close or if you're the world's biggest brick wall photographer. Pincushion distortion is negligible, and correction profiles handle it anyway.
Every photo was tack sharp wide open at F1.8, at both the wide and long end. Most zooms show a flaw somewhere in their range, and this one doesn't. Bokeh transitions are smooth, melting the background into a creamy but still recognizable wash so your subject pops.
Sigma 17-40 vs Fuji Primes
I own literally all of Fujifilm's fast primes, and I've found it hard to recommend any of them over the past few months. The only time I've reached for a prime is to record myself, and even then it's the Sigma 12mm F1.4.
As of recording, the Sigma is $919. In the US, Fujifilm's 18mm F1.4 is $1,200, the 23mm F1.4 is $1,050 and the 33mm F1.4 is $950, about $3,200 total. Yes, the Fuji primes are 2/3 of a stop faster. Whether that's worth the price and loss of versatility is up to you, but I haven't used mine since getting the 17-40. I'm either going to hoard them like the gear goblin I am, or they'll go up for sale.
Who Is This For?
I see it as a direct competitor to Fuji's 16-55mm do-it-all zoom. If you're considering that lens, the 17-40 gives you a narrower range but a big boost in low-light performance and background blur, while staying more flexible than primes.
For video shooters, the internal zoom beats the 16-55's extending barrel and the inflexibility of primes. You also get shallower depth of field than the 16-55, weather sealing, and the option to build out a rig that scares clients into paying more.
It's also for anyone tired of paying OEM premiums. It's cheaper than Fuji's cheapest F1.4 prime and gives you that full-frame look across a flexible range. I love Fujifilm, and I've bought into nearly all its X-mount glass and GFX, but the brand's value gap isn't as big as it was when I bought the X-T3 on release day in 2018. Lenses like the Sigma 17-40 might be what lets new people enter the system without breaking the bank, and that's good for Fujifilm too.
Keep Reading
Did Sigma Make a Better Fujifilm Lens Than Fujifilm? Sigma 18-50mm F2.8 Review
I Shot the 50-140 for 8 Years. Can This Tiny Sigma Replace It?
Gear in This Video
Gear in this video
As an Amazon Associate I earn from qualifying purchases. Buying through these links costs you nothing extra and helps support the channel.
