Sigma Sigma Art Sigma 28-45mm f/1.8 DG DN Art Lens (Leica L) Review

If you're a Leica L-mount shooter looking for a fast, sharp zoom that blurs the line between prime lenses, the Sigma 28-45mm f/1.8 DG DN Art is a fascinating piece of glass. It's a full-frame zoom that stays at a bright f/1.8 throughout its entire range, from a wide 28mm to a normal 45mm. That's a unique trick, letting you zoom without losing light. At nearly 2.2 pounds, it's a hefty chunk of metal and glass, and it's not weather-sealed, so this is a lens built for image quality first and portability second. People often ask, 'is there a zoom lens as sharp as a prime?' With this Sigma, the answer gets pretty close to yes.

The optical performance is where this lens shines. It scores in the 95th percentile for optics, which means it's exceptionally sharp. You get clean, detailed images wide open at f/1.8, and stopping down just makes things crisper. The bokeh is also a high point, landing in the 86th percentile, so your backgrounds will be smooth and creamy, especially at the 45mm end for portraits. The autofocus is decent, sitting around the middle of the pack at the 48th percentile. It uses Sigma's HLA system, which is quiet and accurate for stills, but it might not be the absolute fastest for tracking erratic video subjects. There's no image stabilization, so you'll be relying on your camera's IBIS or a steady hand.

At around $1,414, this isn't a casual purchase. You're paying for that unique constant f/1.8 aperture and the exceptional Sigma Art series sharpness. For a Leica L-mount user, it's a compelling alternative to carrying multiple prime lenses in this range, like a 28mm and a 50mm. If ultimate portability or weather-sealing are your main concerns, the price might be harder to justify.

Let's look at some alternatives. The Viltrox 35mm f/1.7 Z is a fraction of the price and much lighter, but it's a single focal length prime, not a zoom. You lose the flexibility. The Meike 55mm f/1.8 Pro is another prime option that's sharper for pure portrait work at 55mm, but again, you're locked into one perspective. For L-mount specifically, if you need a more versatile, lighter travel zoom, you'd look at something like a standard f/4 zoom from Panasonic. But you give up that beautiful f/1.8 light. The Sigma's real competition is your own bag: a 28mm prime and a 50mm prime. This lens asks if you'd rather have one heavy, brilliant zoom instead of swapping between two lighter primes.

So, should you buy it? If you shoot with a Leica, Panasonic, or Sigma L-mount camera and you value a constant bright aperture and supreme sharpness over everything else—weight, size, and weather sealing—then this lens is a brilliant tool. It's perfect for portrait photographers, event shooters in controlled environments, or anyone who wants prime-like quality with the convenience of a zoom. But if you're a run-and-gun videographer needing fast AF and stabilization, or a landscape photographer hiking miles to a location, the weight and lack of sealing are real drawbacks. For the right photographer, it's a specialized masterpiece.