Intro

The Sigma 17mm f4 DG DN is an ultra wide-angle prime lens for full-frame mirrorless cameras – and spoiler alert, it’s one of the most fun lenses I’ve tested in a while. Announced in April 2023, it’s initially available in Sony-e or Leica L-mounts, and Sigma loaned me a sample to try out.

The 17mm f4 DG DN joins Sigma’s ever-expanding Contemporary I series of compact full-frame mirrorless lenses. All share similar styling and provide affordable access to some interesting focal lengths and apertures.

As the widest model in the series to date, the 17mm is ideal for dramatic landscape and urban photography, as well as being perfect for video work, especially handheld vlogging where the broad coverage can accommodate the crop of digital stabilisation without becoming uncomfortably tight. As you’ll see it also allows impressively close focusing of just 12cm from the focal plane. As always, my complete review is in the video below, but if you prefer to read the written highlights, keep scrolling!

The 17mm is satisfyingly compact, measuring 64mm in diameter, 49mm in length and weighing just 225g – you’ll barely notice it mounted on your camera, and videographers will easily accommodate it on a small gimbal system.

Sigma 17mm f4 DG DN: 64x49mm, 225g

Like previous models in the I series, it has a metal body, ribbed control rings, and weather-sealing at the mount, albeit not throughout the entire barrel. My test sample was made in Japan.

Working outwards from the lens mount is a switch for auto or manual focus, followed by an aperture ring from f4 to f22 in one third increments with an A position for body based control; note, this is not de-clickable. Then towards the end of the barrel is a well-damped manual focusing ring and a 55mm filter thread.

Like other I series lenses, Sigma supplied the 17 with a choice of two lens caps, one a traditional spring-loaded plastic cap, and the other a small metal disc held in place by magnets. The latter is a fun alternative which snaps into place quite satisfyingly, but I mostly used the plastic cap, which is also easier to fit or remove when the supplied aluminium petal hood is fitted. Speaking of which, here’s how that looks.

The lens employs internal focusing with a stepper motor and you’re watching it right now on a Sony A7 IV set to Single AF and at very close range. Some Sigma lenses hunt a little in AFS mode, but not the 17 here which confidently lands on the target without a wobble. 

That said, switching it to Continuous AFC mode does speed things up a little, while remaining accurate. It’s a quick and quiet focuser in use.

Here’s the same test, but for video, filming 4k 25p with a single AF area again in the middle of the frame. It’s not a particularly demanding scenario with an ultra-wide at f4, even at close range, but the lens proves it can be driven smoothly for video use here.

Next for face tracking, again with the lens wide-open at f4 but this time using the full AF area. Here you can see the lens and camera combination easily refocusing on me as I move around the frame. You’ll also get an idea of the broad coverage, ideal for handheld vlogging as I’ll show you later.

Now for focus breathing, here with the lens closed to f22 and manually focusing from infinity to the closest distance and back again. As I focus the lens closer, the field of view reduces a little, but not by a significant amount, especially considering the focusing range you’re seeing is from infinity to just 12cm and back again. As such I don’t think it would become distracting for video in general use.

Ok, now for my optical tests, starting with my distant landscape scene, angled so that details run into the corners. You’re looking at the image without lens compensation here, and now with Distortion Compensation set to Auto where it corrects for some barrel distortion with a minor crop. 

Since this is how the lens is designed to be used, all the images I’ll show you from this point on have lens corrections applied.

Switching to the f4 version and taking a closer look in the middle of the frame – where I focused the lens – shows excellent detail right out of the gate with no benefit in the middle to closing it any further.

This quality is maintained up to f8, but from f11 onwards, the image begins to soften due to diffraction, so I’d only advise shooting smaller than f8 if you absolutely need a broader depth of field.

Returning to the f4 image and moving into the far corner shows the lens maintaining crisp details, although there is some darkening due to vignetting. As you close the aperture, this vignetting lifts and is mostly gone by f8, but again closing it any further will begin to soften the result.

So the Sigma 17 f4 is a decent performer wide-open at f4, delivering a flat field with sharp results from corner to corner. I’d be very happy shooting it between f4 and f8.

Moving on, I realise this isn’t the ideal lens for flattering portraits or shallow depth of field effects, but I still wanted to show you what you can get at f4 from reasonably close range. Like all very wide lenses, you have to be careful about distortion if you get too close to the camera, or move away from the centre of the frame, but if you zoom-in on the details, you can at least see the lens is very sharp in this test.

While 17mm may not be a natural choice for stills portraits, it is perfect for handheld vlogging, where the wider the better. Here’s the Sigma 17 on the recently launched Sony ZV-E1, using IBIS alone, where you can see it’s ideal for capturing the scenery around you. Note the lens does not have optical stabilisation of its own.

Next here’s the ZV-E1 set to Active SteadyShot which allows IBIS to move across a broader area for greater compensation, albeit requiring a minor crop as a result. I measured the crop factor at about 1.12x, making the 17 act more like a 19mm, but that’s still more than wide enough for most.

And finally the ZV-E1 with its new Dynamic SteadyShot mode which applies additional digital compensation for an even smoother result, albeit this time with a 1.44x crop which turns the 17 into a 24 or thereabouts. It’s become tighter, but I think it’s just about acceptable for this kind of video.

Anecdotally I’ve found Sony’s own lenses seem to work better with the various SteadyShot modes, but the results here still give you an idea of what to expect on a Sony body.

So far you’ve seen the Sigma 17 tested from about 50cm or more from the subject, where the f4 aperture can only deliver mild blurring in the background. But its secret weapon is being able to focus much closer still, in turn allowing you to achieve more blurring than you might expect.

So here’s my bokeh ball test with the lens positioned near to its closest focusing distance and with the aperture wide-open at f4. Here you can see not only how sharp the ornament is in the middle, but also the potential for bokeh blobs even though the fairy lights aren’t too far behind.

Taking a closer look at the rendering shows some outlining and textures within the blobs, neither of which is ideal, but viewed as a whole image I don’t mind the result.

Closing the aperture down gradually reveals the shape of the seven bladed aperture system, and as before I’d stick to the f4 to f8 range for the best looking results.

That said if you’re after diffraction spikes, here’s what you’ll get with the aperture closed all the way down to f22.

But I digress, so let’s get back to the close-up performance as it really is a highlight of the lens. Here’s a shot taken as close as I could focus, where the lens is capturing about 100mm across the frame. This roughly confirms Sigma’s quote of 1:3.6 as the maximum magnification at 12cm from the focal plane. 

At this distance the front of the lens barrel is only about 4cm from the actual subject, so you will need to be careful about casting shadows, but there’s still loads of potential for dramatic shots at close range as you’ll see in my sample images.