Sigma 20mm F2 DG DN Review

There was once a time where Sigma was known for their sharp, yet massive lenses.

In (very) recent years, Sigma has done away with that trend, consistently offering new lenses that were still razor sharp but not absolutely gigantic.

Today, I’ll be looking at the Sigma 20mm F2 DG DN, a compact wide-angle prime. It’s relatively new, being released in early 2022 as part of Sigma’s new ultra-compact full frame lineup.

So, how does it stack up against its competitors? Let’s find out.

Looking for a quick summary before jumping in?

Sigma 20mm F2.0

- Incredibly razor sharp

- Fantastic build quality

- Blazing fast autofocus

- Strong vignette/distortion

- A great mid-budget pick

a river in edinburgh scotland

Build Quality

Size & Weight

First up, we’re going to talk about the size and weight of this lens. I’m a huge fan of compact kits, and this one certainly fits the bill.

The Sigma 20mm F2 measures roughly 2.9 inches (7.4cm) and weighs a reasonable 13.1oz (370g). Although not as small as some lenses, it’s a huge improvement when you compare it to Sigma’s old Art lenses.

It’s absolutely great to see Sigma tackling this trend of small-but-sharp lenses. Lenses like this (ultra compact) are what inspired me to originally switch away from my bulky DSLR setup many years back.

When mounted on my Sony a7iii, it literally makes the camera feel like a point and shoot. It easily fits in my camera insert and, if I’m wearing a big enough jacket, it’ll fit into my pocket (albeit, somewhat awkwardly).

Is the lens well built?

Now, the low weight and compact size doesn’t mean there’s a sacrifice in build quality.

The Sigma 20mm F2 isn’t a massive monster of a lens like some of the brand’s other offerings, but it feels well built in its own right.

Lens Barrel

To start, the lens barrel is entirely made of metal. The mount is metal, the focusing and aperture rings are metal, everything is metal.

A lot of Sigma’s latest lenses (like the 90mm F2.8) are adopting all-metal builds, and I really love to see it.


Lens Hood

Even the petal-shaped lens hood is made of heavy-duty metal.

Generally, a lot of manufacturers will opt for a plastic (polycarbonate-type) lens hood, but not here.

Lens Caps (2 of them)

The lens ships with two caps. One is a typical plastic pinch-cap while the other is ,you guessed it, a metal magnetic-style cap. They both work well enough, but I’ve found I tend to frequently lose the magnetized caps on other lenses.

For those who may be interested in using ND filters or polarizers, do note that the Sigma 20mm F2 takes 62mm filters, a rather uncommon size.

Weather Sealing

As for weather sealing, the lens does offer a rubber gasket around the mount, but unfortunately nothing else.

The lack of full sealing is certainly a bummer, but at the price point I can understand why it wasn’t included. This is a relatively mid-budget pick, not something more in the price range of a G-Master.

Built to last?

So is the lens built to last? I’d say yes. Despite the lack of full weather sealing, the Sigma 20mm F2 feels incredibly well built (like a tank!) in my hands.

I’ve had nothing but good experiences with many other Sigma lenses when it comes to long-term durability, so I suspect this one will be similar.

rainy street in edinburgh scotland
Should be able to withstand a bit of rain, but be careful.


Ergonomically, the lens is quite comfortable to use.

The full-metal focusing ring makes for a great gripping point (even if you always keep it on AF), and the lens balances just right on my a7c.

This is the kind of lens that you can easily throw in your bag (or pocket) or carry around all day long and not have any hand fatigue.


When it comes to aesthetics, I understand beauty is subjective but I think this lens is gorgeous.

The body of the Sigma 20mm F2 is quite minimalist (in a way), with the white text engravings popping out against the sleek black barrel.

There’s a lot of clean, angular lines, and the focus/aperture rings are sized “just right”. The iconic Sigma “C” adorns the side of the barrel.

I’ve used a lot of vintage lenses over the years, and this one kind of gives me that vibe. All metal, super clean, and no cheap plastic to be seen.

Already interested?
Sigma 20mm F2.0
The Sigma 20mm F2 is incredibly well built whilst still retaining a small and lightweight size.

Image Quality


Next up, we’re going to be looking at sharpness. My lens tests generally don’t get ultra-scientific, so don’t expect any MTF graphs or anything along those lines. Either way, to be honest, there’s not much to say here…

The Sigma 20mm F2 looks fabulous even wide open. There’s some (extremely) minor corner softness, but it’s so minimal that you’d barely even notice unless you were majorly pixel peeping.

Stopping down even just a bit creates absolutely spectacular results. I’m sure I could nitpick and find flaws, but nope, it just looks great. Shooting landscapes even wide open at infinity is spectacular.

Contrast is strong and color rendering is fantastic.

Optical Quirks & Flaws

Despite the amazing sharpness, the lens does suffer from a few glaring optical faults.


Distortion is by far the biggest hitter.

We see roughly 20% barrel distortion (yes, that much) which can be tough to correct.

Even with built-in correction (Lightroom lens profile), there’s a tiny, tiny bit of mustache-shaped distortion that remains.

It’s… subtle, but still there if you look closely enough. For this reason, the lens could struggle in situations like architecture or anything else that requires straight lines.

river in edinburgh scotland
Distortion is quite strong. Mostly fixable in post-processing but not perfect.


Vignette, as well, is another rough point of the lens. We see heavy darkening on the corners.

I don’t think it would ruin images, but if you’re shooting in low light you’d risk introducing noise when fixing it.

Stopping down does remedy the darkening just a bit, but even by F4 it’s still quite strong.

Chromatic Aberrations

Thankfully, that’s where the troubles end. To counter these bad points: chromatic aberrations are a complete non-issue.

Even in more extreme situations (such as branches against a sunny sky), I couldn’t find any sort of major fringing.


Flare resistance is also incredibly strong.

Even shooting into direct sunlight, I noticed very little ghosting or loss of contrast.

Overall Optical Performance

Overall, the Sigma 20mm F2 DG DN offers excellent sharpness but at the cost of a poor vignette and heavy distortion.

Both these issues can be mostly fixed in post-processing, but you run the risk of getting ruined shots (by either noise or mustache-distortion). Stopping down mostly fixes the vignette, but there’s not much you can do about distortion.

If you’re looking to shoot a lot of architecture, consider something like the Sony FE 20mm F1.8. However, if you’re shooting landscapes or literally anything else, don’t dismiss the Sigma just yet.

edinburgh scotland

Focusing System


Stills AF

Next up, let’s focus on focusing. I generally don’t dig too deep into autofocus as most modern lenses perform “well enough”.

The Sigma 20mm F2 fell into this category, focusing quickly and accurately. Really nothing to complain about.

Continuous subject tracking (AF-C) was quick and reliable. I rarely noticed it missing the mark.

EyeAF, although it rarely works well on such wide lenses, did it’s job decently.

Video AF

Video autofocus was a similar story. Of course, video AF will always be a bit slower than stills, but I found it to be quick and reliable.

The focusing motor is dead silent and the lens exhibits only very, very minor focus breathing.

Manual Focus

My fellow manual focus enthusiasts will be pleased to know that the MF experience is pretty enjoyable.

First up, having the physical AF/MF switch is really handy (don’t have to dig through Sony’s terrible menu system).

Like most modern lenses, it is focus-by-wire, but the ring is well dampened and felt quite accurate.

As usual, Sony’s focus assists such as peaking and magnifier work excellently with the lens.

Already want to check it out for yourself?
Sigma 20mm F2.0
Despite strong vignette and distortion, the Sigma 20mm F2 offers a lot for a mid-budget pricetag.
arthur's seat in edinburgh

Other Notes

Finally, we have a few more random things to cover.

No Stabilization

First up, the lens does not offer any sort of stabilization.

Given the price point, I’m not surprised at all. Plus, most Sony bodies have IBIS now anyways, so the need for stabilized lenses is slowly diminishing.

Aperture Ring

As I mentioned earlier, the lens offers a physical aperture ring! I’m a sucker for on-lens aperture.

You can, obviously, still set it to automatic aperture, but the option is there for people (like myself) who want manual control.

The ring is clicked, which may be a bit of a bummer to video users, but I absolutely love the feel of a clicked ring. Good stuff, Sigma.

Macro Capabilities

For those who may be considered some very casual macro shooting with this lens, it actually is decent.

As you’d expect from a wide angle, the magnification is tiny (0.15x to be exact), but the minimum focusing distance is very close.

You can focus as close as roughly 9in (22cm), allowing you to get some silly and/or dramatic close-up shots.


Finally, I want to touch on astrophotography. Given that this is a bright-aperture wide-angle lens, some photographers may be considering it for shooting the night sky.

The bad news is that the heavy vignette is particularly egregious when shooting photos of stars.

The good news is the coma control is spectacular.

So, while certainly not a dedicated astro lens, it could do the job for someone just wanting to dabble.

milky way
Astro photos look decent, but the vignette darkens the corners a lot.

My Final Thoughts


Before we round out the review, I want to offer a few excellent alternatives.

Sony Lenses

Sony FE 20mm F1.8 G

First up on the list is the fantastic Sony FE 20mm F1.8 G. That lens is an absolute beast.

You’ll find comparable sharpness, similar build/size, and, most importantly, much better vignette and distortion control.

If you’re willing to drop a few hundred more dollars, pick up the Sony instead.


Samyang AF 18mm F2.8

On the flipside, if you’re looking to spend even less money, consider the Samyang AF 18mm F2.8.

Although not quite a sharp and certainly not as well built, the Samyang is a nice little lens that offers a great blend of performance and price.

Tamron 20mm F2.8

For even less money, consider the Tamron 20mm F2.8.

It’s pretty good, but given that it’s so cheap, there’s definitely sacrifices. Build quality isn’t great, it’s not as sharp and autofocus is a bit slower. Worth considering though if you’re looking to go as cheap as possible.

river in edinburgh


Like I said, if you can spend a few hundred more dollars, definitely shoot for the Sony FE 20mm F1.8 G instead.

However, if you’re looking for a great mid-budget pick, you really can’t go wrong with this lens.

Despite the distortion and vignette, the Sigma 20mm F2 still offers spectacular sharpness, great autofocus and a bulletproof build all for a pretty reasonable price.

When it comes to lenses that are this sharp yet small, some sacrifices had to be made. Although the distortion is rough to fix, the vignette can be largely remedied by stopping down and in post-processing.

Once again, if you’re on a budget, I do honestly think this lens is a good pick. So, I’ll leave a purchase link below for your consideration.

Thanks for reading! 🙂

Compact | Razor Sharp | Well-Built
Sigma 20mm F2.0
Despite some drawbacks, the Sigma 20mm F2 offers fantastic sharpness, a robust build, and a reasonable price.

Disclaimer: Some links in this article may be affiliate links, which means I get a (very small) commission if you purchase things through my links. If you do, thank you for the support! <3