Sigma 20mm and 24mm f/1. 4 DG DN Review: Top Lenses for Sony E-Mount

Sigma 20mm and 24mm

The two new wide-angle lenses that Sigma has just introduced are sure to please many people thanks to their wide apertures and affordable prices.

Sigma will make these lenses in both Leica L and Sony E mounts. For this review, I used the Sony E-mount versions on a Sony Alpha 7R III.

Build Quality

Weighing one pound, 6. 2 ounces (630 grams) and measuring 4. 5 inches long by 3. 5 inches in diameter (113. 2 by 87. 8 millimeters), the 20mm f/1. 4 is the bigger brother of these two new wide-angle primes. In comparison, the 24mm f/1. 4 weighs one pound, two ounces (510 grams) and measures 3. 8 inches long by 3 inches in diameter (97. 5 by 75. 7 millimeters).

Sigma 20mm f/1.4 DG DN Art lens.

Sigma 24mm f/1.4 DG DN Art lens.

The build quality of both lenses is very similar and, in fact, are designed to be familiar in use with the other currently available f/1. 4 DG DN lenses: the 35mm and 85mm. All lenses are made from Sigma’s trusted thermo-composite exterior. There’s a mixture of semi-gloss and matte finishes. Although I believe the whole lens would look better in a matte finish, everyone will have different opinions.

The two lenses are equipped with matching rings, buttons, switches and switches. The first is the aperture ring. This can be used to adjust the f stop directly or it can also lock to the “A” setting which allows the camera to operate the shutter. These lenses may also be de-clicked with the on-off switch to the left side. It will click loudly when it is on. The ring is easy to control and maintains a good fluid tension when it’s off. It’s easy to use one hand to adjust the f-stop by moving it up and down several times. This ring has plastic ribbing.

Switch panel as seen on the 20mm.
Aperture lock as seen on the 24mm.

Moving up on the lenses there is a focus mode switch, a rubberized focus lock button that’s customizable in the camera’s menu settings, and a manual focus lock switch. The manual focus lock switch is interesting because I don’t remember other lenses I’ve used that have one. What this function will do is allos you to disable the focus-by-wire operation of the large focus ring. It’s not uncommon in astro and landscape photography to switch to manual focus to hold a point of focus for a longer period of time, and this takes it to the next step where the ring cannot be accidentally nudged by a couple of degrees either once it’s set. These features are great because they were a direct result of real photographer’s requests.

Speaking more about the focus ring, it does have rubberized ribbing, unlike the aperture ring. The ring is very comfortable and has no play in its rotation. It glides smoothly once it gets in motion, but it is a bit on the stiff side.

Front element of the 20mm.
Rear gel filter holder as seen on the 24mm.

The front of the 20mm lens has 82mm filter threads and the 24mm has 72mm filter threads. However, these lenses also have a rear gel filter holder. I haven’t picked up on the appeal of lenses that have rear filter holders for gels since it’s still totally confusing on which gels are pure enough for optics and which are for lighting equipment and I can’t be the only one. If they offer this, I would hope that the manufacturers of lenses included a range of gels or gave specific recommendations about what products to use.

Image Quality

The Sigma 20mm f/1. 4 DG DN Art uses 17 elements in 15 groups, including two SLD and three aspherical elements. The Sigma 24mm f/1. 4 DG DN Art uses 17 elements in 14 groups, including two FLD, one SLD, and four aspherical elements. Both lenses have Super Multi-Layer Coatings like current Sigma lenses. They also both use Nano Porous Coating. Both of these coatings are to suppress flare and ghosting issues.

20mm at f/16
24mm at f/16
Shot with the 20mm
Shot with the 24mm

The image quality looks outstanding for both lenses when at their best, and still perfectly fine when some effects like lens flares crop up. The flaring becomes more noticeable the more the lenses are stopped down and, for the most part, it is tasteful and not too heavy. As far as color fringing — otherwise known as chromatic aberration — this, too, is well controlled for both, and I didn’t notice anything pop out at me when shooting with corrections turned on in the camera.

It is difficult to see the vignetting in wide-angle lenses. It cleans up quickly as the lens is stopped down, but you will need to make some corrections needed in post if this is not the desired effect. Sigma provided a profile correction for me prior to launch. It worked without any additional effort. Once the lens begins shipping to customers, these automatic corrections should be made available in popular photo editing software.

Shot with the 20mm.
Shot with the 24mm.
Shot with the 24mm.

Taking a closer look at image sharpness, I saw that for the 20mm lens, it held together really well throughout the aperture range. At the center of the image, f/8 was perhaps the best, but it was hard to tell when everything looked good. There was a slight dip at f/16, the lens’ maximum aperture. At the corners, f/5. 6 through f/8 looked sharpest.

Sharpness for the 24mm was a similar story, with f/8 looking overall the best at the center and f/8 being the best at the corners.

Shot with the 20mm.
Shot with the 24mm.

These lenses both feature an 11-bladed rounded aperture and the quality of bokeh they produce is wonderful. These lenses have a large field of view, and a shallow depth of focus. This adds depth to the scene.

Choices, Choices

After spending some time with both optics, I am finding that I am a fan of both of these new lenses. It is difficult to choose which lens I would recommend. Having both of them in my camera backpack at the same time, I had no strong feeling of going with one over the other in any situation: they come away with comparable results in every way. They are the large and small ones.

If it really does boil down to that for you, I think I’d have to recommend going with the small one — the 24mm — unless you are quite certain that you need the slightly wider angle of view.

Shot with the 20mm.
Shot with the 24mm.

Are There Alternatives?

While the Sigma 20mm f/1. 4 DG DN is the only 20mm f/1. 4 lens available other than the Sigma DSLR 20mm lens it is replacing, I still think it has some tough competition with the Sony 20mm f/1. 8 G. With the Sony, we obviously lose two-thirds of a stop of light however, the benefits to going with the Sony for the same $900 price show themselves in weight and size: the Sony 20mm is only 13. 2 ounces in weight and is 3. 3 inches long and three inches in diameter.

The Sigma 24mm f/1. 4 is probably the best you can do at this price, but Sony does offer its highly-popular 24mm f/1. 4 G Master lens for $1,300. This is many hundreds of dollars more expensive than Sigma, but it’s actually harder to tell the clear and obvious benefits in this case. Perhaps side-by-side testing would prove one over the other, but I would go with the Sigma for the lower price and comparable specs.

Should You Buy Them?

In both cases, yes. Sigma has proven with the f/1. 4 DG DN Art series that it is not trying to make lesser versions of Sony’s best lenses to fill in some niche, but instead are downright in direct competition against them — and successful in this endeavor, I might add.