Sigma Launches “I Series” with New 24mm, 35mm, and 65mm Mirrorless Lenses

Continuing to add to its growing DG DN lineup of full-frame mirrorless lenses, Sigma has just released a trio of new lenses, along with a new designation for lenses that are sleek and stylish. Introducing the 65mm f/2 DG DN Contemporary, 35mm f/2 DG DN Contemporary, and 24mm f/3.5 DG DN Contemporary lenses, Sigma is making a statement with these primes by favoring modest and useful lens designs, rather than focusing solely on speed at the expense of size and weight.

Dubbed the “I Series,” which includes the three new lenses being announced today, along with the previously released 45mm f/2.8 DG DN Contemporary, these lenses share a common design language that prioritizes smaller form factors and stylish exteriors compared to the big, fast, and heavy designs Sigma became so associated with after years of releasing so many f/1.4 primes for SLR systems. These new lenses take the different path of being ideal for handheld, walkaround shooting, and also take into account the types of cameras with which they’re being used. Available in Sony E-mount and L-mount versions, I Series lenses are compact lenses for compact system cameras. Their slower designs can be mitigated by these cameras’ IBIS systems and more advanced processing for working at higher ISOs. Additionally, it’s worth mentioning that the I Series is a separate designation from the Art, Sports, and Contemporary labels; while the first four I Series lenses all happen to be Contemporary lenses, it’s possible there will eventually be Art and Sports type I Series lenses.

I was fortunate enough to get my hands on a couple of the new I Series lenses and, as an L-mount shooter, I also already had the 45mm f/2.8 lens. I’ve already commended the 45mm in a review when it was announced, so I was really excited to get a similar handling experience with new focal lengths. I was only sent the 65mm f/2 and 35mm f/2 lenses to try out for a week during this end-of-fall season, so hopefully will be able to get my hands on the especially compact 24mm f/3.5 sometime in the future.

It’s nice to see that a familiar design is going to be one of the unifying concepts for the I Series. The 65mm and 35mm lenses match the knurled design and all-metal housing of the 45mm, with one key difference being the shape of the AF mode switch, which is a bit easier to manipulate with one hand compared to the 45mm’s switch. All of the lenses also include nice metal lens hoods, and the new lenses are being packaged with metallic, magnetic lens caps (more on this later). One criticism I do have from a form-factor standpoint is the changing of filter diameters between the different focal lengths (55mm for the 24mm, 58mm for the 35mm, 55mm for the 45mm, and 62mm for the 65mm). Fortunately, I’m not much of a filter user, but it would be nice to see a standard diameter to further unify this already very tight-looking series of lenses.

Performance-wise, it’s not surprising to me that Sigma managed to keep a similar look and feel as compared to the 45mm. All three lenses have a punchy color quality and similar rendering of light, and all handle flaring quite well. I didn’t dig into doing strict sharpness tests so much, but from a usable perspective, they’re all managing exceptionally well on the 24MP sensor of my Sigma fp. There isn’t any overwhelming distortion on any of the lenses, nor any visible aberrations or unbearable color fringing that I could find.

It’s also worth calling out the proverbial elephant in the room with these lenses: it’s true, they’re not fast lenses. You might even get away with calling a couple of them decidedly slow. I argued my point on this topic with the original 45mm, and I’ll stand by it with these three new lenses. I will lighten up a bit, though, because the two lenses I was working with were f/2 designs, and objectively were in the “bright” realm of lens speeds. Despite their maximum apertures, I tended to stop down a few stops when possible, just in the same way I would with pretty much any other lens. In my opinion, you look for the fastest lenses to use at their widest apertures, and with any other lens you’re looking for the versatility of using it in the middle range of f-stop choices.

Focusing on the 35mm f/2 DG DN for a moment, this lens stuck out to me due to its size, of course, and how it’s just a fun and natural lens to work with. I’m not going to deny that the 35mm focal length is one of my least favorites, but somehow, I keep being pleasantly surprised each time I pick up one of these lenses to use. The focal length-aperture combo isn’t going to yield any spectacular shallow depth of field images easily, but if you use it wide open, you can get a nice, natural hint of subject separation that pulls your subject away from the background without losing context. Optically, SLD and aspherical elements keep things sharp and color accurate, and this lens also has a nine-blade diaphragm that should render bokeh smoother and rounder.

Regarding the longer of the two lenses I used, the 65mm f/2 DG DN, I had a strong feeling I was going to click with this lens and that was certainly true. It’s a strange focal length, to be sure, but I think it’s worth a try since it might perform the duties of a 50mm with more selectiveness or offer a bit more breathing room than an 85mm. Compared to the 35mm, the f/2 design of this lens offers quite a bit of depth-of-field control with midrange subjects and is honestly all that was needed to throw a background out of focus and separate a subject. I really enjoy working with these slightly narrower focal lengths because they let you pick things out of a scene and focus your attention on details in a natural way. Unlike a macro lens or a super telephoto, using just a short tele to pick out subjects retains a bit of context of the scene while clearly diverting attention to one area. Optically, this lens, too, uses aspherical elements and SLD glass to achieve well-corrected imagery, and the nine-blade diaphragm helps smooth out blurred backgrounds.

Additionally, even though I didn’t get a chance to shoot with it, I’ll point out that the 24mm f/3.5 DG DN has a similar design, although it prioritizes size even more due to its f/3.5 maximum aperture. What’s even more unique is the 1:2 maximum magnification ratio with this lens and 4.25" minimum focusing distance, which makes it a good choice for some close-up wide-angle shooting.

It’s also worth mentioning that all the I Series lenses (so far) have internal focusing designs and use stepping AF motors that are super quiet and super quick. The fp isn’t the fastest-focusing camera out there, so the lenses had no trouble keeping up with that, and even performed beyond my expectations with some moving subject shooting. Switching over to manual focus on the lenses is handled by a rear switch, and manual focus feel is fine, but it’s not the go-to mode I’ll be working with on these lenses.

Finally, in addition to the lenses themselves, Sigma is also releasing the CH-11 Magnetic Cap Holder. Yes, a lens cap holder. Normally, something like this wouldn’t get much airtime on Explora, but we’ll make an exception for this one because I feel like its incorporation into the system’s ethos is important. Usually, most lenses simply come with a snap-on, center-pinch type cap, and that’s the cap you get and that’s that. These new Sigma lenses come with this snap-on cap as well as a new Metallic Lens Cap that magnetically attaches right to the front of the lens, no adapter ring needed. The caps themselves have a small felt patch on the back to prevent scratching and have a raised platform on the front for grabbing, and then the CH-11 is simply a metal ring for holding these magnetic caps while shooting. It’s nothing mind-blowing but is a fresh and smart execution of an accessory we all use.

I’m really excited to see what’s next for the Sigma I Series, and I’m excited that Sigma is making moves in this direction. As someone who’s usually looking for enjoyment when taking photographs, these are the types of lenses I seek out. They’re not competing with your ultra-fast primes or speedy zooms; they’re lenses built for walking around and taking photographs. They fit perfectly on your sleek full-frame mirrorless and aren’t a burden to hang onto when you spend several hours on your feet. I even went on a 50-mile bicycle ride with the two lenses and a camera body tucked into my jersey pockets—which is not something I’ll be attempting with a 35mm f/1.2 anytime soon. The I Series are fun lenses but don’t lose sight of having excellent focusing performance and optical quality.

What are your thoughts on the Sigma I Series? Are you interested in these more modest and versatile primes or do you favor the faster and more exciting lenses? How do you feel about losing some speed in order to gain a smaller, lighter-weight lens? Let us know your thoughts on Sigma’s newest trio of lenses in the Comments section, below.