For the longest time, Sigma was known for making lenses that were optically excellent but, unfortunately, absolutely massive.
In recent years, Sigma has done away with that trend, introducing lenses that offered a much better blend of optical quality and size.
In this particular review, we’ll be looking at the Sigma 90mm F2.8 DG DN, an ultra-compact telephoto prime. This lens is rather new, releasing in late 2021 as part of Sigma’s new ultra-compact “I-series” lineup.
So, how does this little F2.8 lens stack up against it’s larger competitors? Let’s find out.
Looking for a quick summary before jumping in?
- Very small and compact
- Excellent all-metal build
- Fast and reliable AF
- Physical aperture ring
- Great option if you're ok with F2.8
Size & Weight
So, first up let’s talk about size and weight, as that seems to be the biggest strength of this lens.
The Sigma 90mm F2.8 measures a length of 2.4in (6.1cm) and weighs a rather minimal 10.4oz (295g). This is INCREDIBLY small especially when you compare it to some of Sigma’s old Art lenses.
I understand that a 90mm lens at F2.8 is a bit of an odd combination, but I love it. As a fan of small kits, these kinds of lenses are what originally got me to ditch my giant DSLR setup.
It makes my a7iii feel like a point-and-shoot, and it even fits perfectly into my Tenba BYOB 10, something that a lot of telephoto FF lenses can’t do.
Is the lens well built?
Now, being small and compact doesn’t necessarily mean poor build quality.
The Sigma 90mm F2.8 isn’t an absolutely heavy and gigantic monster like some of the brand’s other offerings, but it feels well-built in its own right.
First up, the lens is crafted completely out of metal. From the mount all the way up to the front element.
Many lenses offer a mix of metal and plastic polycarbonate, but nope, this one is just straight up pure metal. Feels great.
Even the lens hood is made of metal. It’s grippy and feels quite durable, just like the rest of the lens.
It should be noted that the hood is almost as large as the lens itself, so you’re effectively doubling the length of the lens when attaching it.
It may seem strange to dedicate a whole section to the lens caps, but Sigma has done something interesting here: they’ve offered the user two choices.
First, you have the traditional pinch-on cap that you’d see on almost every other lens in existence. It does the job well.
Second, they make use of the full metal design to offer a magnetic cap that just pops on and off. Very, very cool.
Sigma has also opted to include a padded carrying bag, reminiscent of their Art series lineup.
This may seem minor, but it really adds an extra premium touch to the lens.
As for weather-sealing, the Sigma 90mm F2.8 offers just a gasket around the lens mount.
This lens is small and pushes into the low/mid budget range so while I would have liked to see full weather sealing, I can understand why Sigma opted out.
Built to last?
So does the lens feel durable and long-lasting? I’d say yes.
Despite the small size and lack of full weather sealing, the lens is built like a tank.
So yeah, between the full-metal build and the gasket seal, this lens really does feel beefy and built to last.
Next up, let’s talk about ergonomics. Like I stated prior, I’m a big fan of compact lenses, and this Sigma certainly fits the bill.
The Sigma 90mm F2.8 balances perfectly on my a7iii, allowing easy and comfortable one-handed use. The all-metal build can get a bit cold during chilly temperatures, but that’s just a really nit-picky type complaint there.
The large focus ring provides a nice gripping point, and I love being able to adjust aperture physically (more on that later).
This is the kind of lens that you can toss in your bag or carry around all day long and not get tired.
As for aesthetics, beauty is subjective but I really dig the look of these new I-series lenses.
The lens barrel is quite minimalist, with the white text engravings popping against the sleek black metal.
The focus and aperture rings are perfectly sized to look “just right”, and the Sigma “C” adorns the side of the barrel.
I really love the look of all-metal lenses, they remind me of the standard prime setups on old film cameras (I shoot a lot with old FD glass).
Next up, let’s go over sharpness. My sharpness tests don’t get very scientific, so don’t expect any MTF graphs or anything like that. I generally just pixel-peep to the extreme.
Shooting wide open, the lens is pretty much razor sharp. Stopping down makes virtually no difference, as the frame is already near flawless from edge-to-edge.
I find that a lot of short telephoto lenses are ridiculously sharp, and the Sigma 90mm F2.8 is really no exception.
Optical Quirks & Flaws
Sharpness is all well and good, but does the lens suffer from any sort of optical quirks or flaws? A bit, actually.
First up, distortion. The lens suffers from some pretty substantial pincushion distortion.
It’s rather linear and predictable though, so it’s usually easily fixable in post-processing.
Not a huge deal, but something to be mindful of if you’re photographing a lot of straight lines.
Vignette is similar, showing roughly -1.5EV at the edges of the frame.
Once again, fairly easy to correct in post, but due to the F2.8 nature of this lens, you may introduce digital noise when shooting in lower light conditions.
As for flare, the lens suffers a bit, but only in certain circumstances.
Shooting directly into sun shows a pretty noticeable lack of contrast and minor ghosting/artifacts.
Using the lens hood and just being cautious about your composition goes a long way, however, and I don’t expect the flare resistance to be a big problem in most situations.
Finally, chromatic aberrations. There doesn’t seem to be many issues with CA besides a little bit of fringing in more extreme circumstances (such as branches against a sunny sky).
Generally, a single click in post-processing will eliminate anything that pops up.
Being an F2.8 lens, you may not expect world-shattering bokeh, but the 90mm delivers some pretty nice results.
Subject isolation is pretty nice, and transitions from focused-to-unfocused are quite smooth and pleasant.
It’s not a bokeh master like the 85mm F1.4, but it does the job well.
Overall Optical Performance
Overall, the Sigma 90mm F2.8 DG DN delivered some excellent optical performance.
While it’s easy to criticize the distortion and vignette, those are issues that are generally easy to fix in post-processing.
Sharpness is spectacular, just as we’ve come to expect out of Sigma lenses. Images show a lot of character, with strong contrast and nice color balancing. Really happy with the performance overall.
Next up, we’re going to focus on focusing. I generally don’t dig to deeply into autofocus, as most modern lenses perform “well enough”.
The Sigma 90mm F2.8 definitely wasn’t flawless, but it performed pretty well overall.
I noticed a slightly higher rate of missed focus with EyeAF versus other comparable lenses, but it was still very acceptable.
Focus tracking is in a similar vein, the AF on this lens is quick, but it did struggle a bit with high speed tracking action (dogs at a dog park).
Again, not perfect, but still more than adequate for most users. Maybe don’t use this lens for a high-speed professional sports job…
Video AF is a bit different, however. It’s quite accurate, but suffers from a few issues.
First up, there’s some minor focus breathing that is fairly noticeable. I don’t think it would be a dealbreaker for most videographers.
Second, the focus motor is loud enough to be picked up by the onboard mic of my camera. Ideally you’d be using an external mic as the onboard one is generally pretty poor anyway.
So, video AF isn’t perfect, but I think it does the job well enough. Either way, manual focus is always the way to go if you want perfection.
Speaking of manual focus, I enjoyed using MF on this lens. The ring is focus-by-wire, of course, but it still feels well dampened and fairly reminiscent of an actual fully manual lens.
The AF/MF switch is a nice addition (I hate digging through menus), but I did find that it was a bit small. As opposed to putting it vertical to fit the small lens better, Sigma instead made it horizontal, which can make it tough to switch as it’s very tiny.
The focus ring itself is a good size, and I found it to be a nice gripping point even when shooting in AF mode. Sony’s excellent focus assists such as magnifier and peaking work great.
This isn’t a dedicated macro lens, but I figured I’d still touch on the subject of macro.
The minimum focusing distance is 18in (45cm), so you’re not going to get super close with this lens.
Magnification rate comes to about 1:5, which isn’t even remotely comparable with a dedicated macro lens, but it does beat out a few other primes in this focal range.
I’d say this lens is usable for some VERY casual and general macro work, but definitely not anything too intense.
The Sigma 90mm F2.8 also has a physical aperture ring! I personally LOVE physical aperture rings so this was a great addition to see.
It’s very well dampened and clicked, so I rarely found myself bumping it out of place accidentally.
For those who wish to shoot auto, you can still set it to A mode. There’s a nice little bit of resistance when turning the ring over to auto mode, which I appreciate.
On an unfortunate note for video shooters, you can not declick the aperture ring.
Finally, one last random note about filter size.
The front filter thread supports 55mm filters and doesn’t rotate when refocusing.
Sigma’s other I-series F2.8 lenses support 55mm filters as well, so it’s nice to see they’ve sort of “consolidated” the lineup.
My Final Thoughts
While the Sigma 90mm F2.8 DG DN is an excellent lens in its own right, I want to offer a few alternatives before we finish out this review.
If you’re looking at a lens like this, you’re probably a lot more concerned about size and weight over getting the brightest max F-stop.
For this reason, I’m going to skip the F1.4 primes and just list lenses that are also small and compact. There’s really no other 90mm F2.8 lenses out there.
Sony FE 85mm F1.8
First up is the Sony FE 85mm F1.8. It’s not quite as compact as the Sigma, but it offers great performance at a similar price.
The Sigma is still better in most ways, but the Sony is a solid pick if you’re looking for F1.8. Feel free to read my review on it.
Viltrox 85mm F1.8
The Viltrox 85mm F1.8 is similar, offering great performance but at a cheaper price.
The Sigma, once again, is still superior in many ways, but the Viltrox is a good pick if you’re looking for F1.8 on a budget.
Is it worth it?
To be honest, there’s really no direct competitor to what the Sigma 90mm F2.8 DG DN offers.
If you’re a daytime/good light photographer and don’t need the extra stops, the F2.8 aperture is more than adequete.
The bokeh rendering is still nice (even at F2.8), the lens is razor sharp, it’s built like a tank, and it can literally fit in my pocket. Overall, a big win in my book.
Where to buy?
If you’re interested in picking up this cute little lens for yourself, I’ll leave purchase links down below.
If you use my links to purchase through Amazon or B&H, I get a (very small) commission at no extra cost to you.
If you’d prefer to try it before you buy it, consider using Lensrentals. Clicking my link gets you $25 off your first rental.
Thank you for your support and thanks for reading!