Sigma 28-45mm f/1.8 DG DN Art Review: Limited Zoom, Maximum Light

Sigma introduced the world’s first full-frame, mirrorless, f/1.8 lens: the 28-45mm f/1.8 Art. But if no one has ever made a lens like this before, do we even need it? Let’s look at the facts with this rather odd entry and see if it’s a hidden gem or a mad science experiment.

The Sigma Art lens series has a rather illustrious history, delivering excellent image quality and rugged construction at a price that most could afford. This isn’t the first time Sigma has made an f/1.8 zoom lens either. The 18-35mm and 50-100mm are both f/1.8 zooms but they are designed for the smaller APS-C sized sensors. It’s not quite fair to compare these lenses simply by the metric of an f/1.8 aperture as a result. Sigma also released a 24-35mm f/2 lens which comes very close, however, the fact that we now have the option for a full-frame f/1.8 lens is quite an achievement. Does that extra light come with some compromises though?

A man and a woman sit side by side on a bench in an urban setting. The man, wearing a T-shirt, and the woman, in a sports outfit and visor, both face away from the camera. Behind them are buildings with visible signage, and a construction area is also in view.
The Sigma 28-45mm provides the shallow depth-of-field and fast shutter speeds we would normally buy primes for.
Photo of a black Sigma camera lens with lens hood, placed vertically on a wooden surface against a dark background. The lens has multiple adjustment rings and a visible brand mark.
It’s a beauty but it comes with a heavy weight and bulky body.

Sigma 28-45mm f/1.8 DG DN Art: How the Lens Handles

Where no compromise has been made is in the excellent build quality of the new 28-45mm. Art series lenses have always been made to a high standard and the 28-45mm carries this tradition forward with a solid metal chassis and full weather sealing. This, coupled with the fast f/1.8 aperture, comes at the cost of weight and bulk. The unfortunate trade-off is the rather heavy 33.5 ounces (950 grams) heft and rather large lens dimensions. At the front is a large 82mm filter thread and button-release hood and the 28-45mm is significantly heavier than a trio of similar apertured prime lenses and takes up about as much space. We do get a lot of nice features on this lens though, with custom buttons, smooth focus and zoom rings, and a classic aperture ring with smooth or click-stop operation.

A close-up view of a DSLR camera lens with a lens hood attached, resting on a wooden surface. The background is dark, focusing attention on the lens's glass elements, which slightly reflect light green hues.
It’s not just heavier than a trio of prime lenses, it’s also well over the weight of a modern 24-70mm f/2.8 lens too.
Close-up image of a person's hand adjusting the zoom ring on a camera lens. The lens markings indicate it is a 28-45mm f/1.8 model, with various aperture settings visible. The lens is black and the background is out of focus.
I like all the controls and rings on the new Sigma Art lens. It handles very well despite its size.

It has a manual focus switch but what it doesn’t have is a way to mechanically decouple the manual focus to avoid accidental adjustments. This is a nice option to have for astrophotography or studio setups when you simply want the focus to stay put no matter what. There is also no built-in image stabilization at all so you’ll be relying on in-camera sensor stabilization.

When it comes to autofocus performance though, I have zero complaints. The linear motors drive the lens elements very quickly and focusing from near to far is rapid.

A man with a beard and short hair stands with arms crossed, gazing thoughtfully into the distance. He's wearing a black t-shirt with a large "C" printed on it. Behind him is a modern sculpture and tall buildings against a blue sky with clouds.
The 45mm focal range is handy for street shooting and portrait work, especially when compared to the older 24-35mm lens.
The image shows a bright sun in a clear blue sky, casting light over blossoming tree branches. The branches are filled with white flowers. Small particles or pollen can be seen floating in the air, illuminated by the sunlight.
Springtime means pollen time. The Cottonwoods and Poplars are filling the air with fluff.

Sigma 28-45mm f/1.8 DG DN Art : How the Lens Shoots

One of the first things I tested for was LoCA or longitudinal chromatic aberration. If a lens performs poorly here you’ll get color shifts in the out-of-focus areas of your image. This is very hard to remove afterwards but happily, the Sigma 28-45mm exhibited almost none to worry about.

Sharpness is key and this is where I was skeptical of the performance. I ended up being surprised with how well the lens did on our test charts but there are some issues. Center sharpness at 28mm showed good detail even at f/1.8 but there is a lack of overall contrast. Steeping the lens down helps correct for this and gives good sharpness and contrast. The corners are correcting for some lens distortion for sure, and this can cause blurriness to the image. At f/1.8, the corners are soft, and stopping down to around f/4 helps out in a big way to correct for this.

A comparison image showing a test chart with various resolution patterns and a banknote in two different apertures: on the left, 28mm at f/1.8 and on the right, 28mm at f/4. Each side displays differences in sharpness and contrast.
Center sharpness is good even at f/1.8. Contrast is low but that can be fixed with a tighter aperture.
Two side-by-side photos of a Canadian one-dollar bill clipped above a series of black triangles on a grey background. The left image is labeled "28mm @ f/1.8," and the right image is labeled "28mm @ f/4." Both display different depths of field.
Corner sharpness at 28mm leaves something to be desired. There is some distortion correction going on causing some blurriness.

At 45mm the lens is slightly more consistent but the center of the image at f/1.8 does still lack contrast. Corners are better, though, even wide-open and the whole image improves with a little tightening of the aperture. The new Sigma lens is absolutely usable at f/1.8 which is a good thing; that is the main reason for this lens to exist. However, sharpness does benefit from an even slightly tighter aperture setting and I would do this when I could afford to.

A man is wearing a vibrant, multicolor outfit with swirling, psychedelic patterns, a headband adorned with pineapples, and large reflective sunglasses. The background features a colorful mural with various abstract and cartoonish designs.
There is no faulting the engineering behind the Sigma Art lenses. They take fun pictures.
Black and white image of a child sitting alone on a sunlit pavement near a tree in a large, empty, urban square. The tree and child create distinct shadows on the ground. A trash bin is nearby and buildings are visible in the background.
I liked the convenience of having a zoom for street shooting but the limited zoom range still left me wanting.

Now, a 28-45mm zoom range doesn’t exactly cover a huge amount of lenses but one thing the Sigma can do is the occasional close-up picture. At the 45mm mark, the lens gives about 12 inches of distance from the sensor plane and about 1:4 life-size reproduction. More importantly, it is also sharp up close and becomes a handy walk-around macro lens for more casual work.

A close-up of a cluster of blooming petunias, featuring delicate white and pink flowers with green leaves. The background is blurred, showcasing a red brick building and a circular sign, emphasizing the beauty of the flowers in the foreground.
Impromptu close-up work is easily handled by the 28-45mm lens and the backgrounds are nice and soft.

Flare is also well-controlled with very little loss of contrast even towards direct sunlight. There is basically no ghosting when shooting wider apertures and only a small amount when stopped down. You might be happy to know that this lens delivers decent sunstars — I know I was. The sunstars can get a little blurry looking but the stars themselves have long points and lots of them. The overall look is fairly dramatic and for any city or landscape shooters, this is a good result.

A bronze statue of a person shading their eyes with a raised hand stands amidst a backdrop of a building and green trees. The sun peeks through the statue's fingers, creating a starburst effect.
Flare is very well controlled and the sunstars are pretty good too. Some ghosting shows up but it is minor.

Bokeh is very important on an f/1.8 lens because shallow depth-of-field is rather easy to achieve. The specular highlights at f/1.8 show a very smooth and clean bokeh with a somewhat strong cat’s eye effect. Stopped down, the highlights become pleasant and round with no major onion-ring look or strong haloes. More importantly, this gives the transitions throughout the focus range a very smooth and natural look which means clean backgrounds and no distractions.

A man with short dark hair and a beard is looking slightly upwards with a contemplative expression. The background is out of focus, with warm, circular bokeh lights creating a cozy atmosphere.
An f/1.8 lens should have nice bokeh and the Sigma 28045mm does not disappoint.

Sigma 28-45mm f/1.8 DG DN Art: Small Zoom Range But Big Versatility

What the Sigma 28-45mm lacks in zoom range it seems to make up in versatility and the results are sharp and optically well-corrected. The 28-45mm lets in lots of light and can handle the occasional macro shot, too. This also has lots of potential as a video lens with its internal zoom which remains balanced as you shift it; perfect for gimbal work.

There is some lens breathing present but it’s more manageable at 45mm than it is at 28mm. I could see this lens being very useful for a video event shooter who needs quick zooming and a wide aperture to capture the action indoors. In the photo world, I feel like landscape shooters will want something with a wider zoom range going to at least 24mm or more. Street shooters may like the convenience of a zoom but I feel that most people would be better served with some compact prime lenses instead. Regardless of whether this lens is right for you or not, there is no faulting the reasonable $1,349 price. For the performance and the specs, I expected it to be a lot more expensive.

A person is operating a professional video camera while wearing a leather jacket and black gloves. The individual is also wearing large over-ear headphones. A red arrow is pointing to a component on the camera, highlighting a detail.
The classic video lens for APS-C cameras was the Sigma 18-35mm f/1.8. The new Art lens can certainly carry the mantle forward for full-frame sensors.

Are There Alternatives?

The Sigma Art 24-35mm f/2 lens would probably be better suited to a landscape photographer and the wider angle coverage is more suited to different genres of photography. Other than that, though, Sigma has once again made a unique optic with no direct competitor.

Should You Buy It?

Maybe. Videographers might get a lot of value out of this lens, as well as any concert or event photographers who need maximum light. It’s versatile enough as a lens but also easily replaced with affordable primes or a general-purpose pro lens giving up a little light.