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. They both have Super Multi-Layer Coating like all current Sigma lenses and both also 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 Spherical aberration, along with spherochromatism, or a change in the amount of spherical aberration with respect to color (looks quite similar to axial chromatic aberration but is hazier) are other common lens aberrations to observe. Stunning power of the Art series lens in a compact body: Explore the versatile potential of "24mm F1.4" with SIGMA Join the lineup of high-performance lenses with the SIGMA 24mm F1.4 DG DN | Art, part of the renowned Art series, delivering unbeatable expressive performance for artists

While this lens produces sharp center of the frame details at minimum focus distance at f/1.4, expect the image periphery to be soft due to field curvature. In regards to the Sony E-mount version of this lens, Sigma develops, manufactures, and sells lenses based on the specifications of E-mount, disclosed by Sony Corporation under license agreement. Although this lens can be used with a close subject rendered large in the frame, lenses such as this one are often used at normal (or even long) subject distances. Capture clear, precise images in any situation with the dust- and splash-resistant SIGMA 24mm F1.4 DG DN | Art lens, designed to withstand challenging environmentsAn 11-blade count diaphragm will create 22-point sunstars (diffraction spikes) from point light sources captured with a narrow aperture. Hanging out under the stars is great fun, and the photographic results from these times take the fun far into the future. Here is where the rubber meets the road, in my mind. When a company like Sigma elects to completely abandon the idea of building a compact lens, their lenses must stand solely on their optical performance. And, in fact, that is largely what Sigma has successfully done. Many people associate the ART brand with optical excellence. Is that true of the 24 ART, particularly since it is (by a fair margin) the largest option of its focal length in the Sony system? We’ll explore that in this section, as the answer is a little, well, nuanced. It should be noted that optical formula of the FE version of the lens is identical to Canon EF or Nikon F mount lenses, so if you are considering the lens in those mounts my observations will be equally applicable. Distance information is relayed to the camera, so the Nikon body can do all the advanced exposure-related stuff with this lens. [+] For owners of Nikon DSLRs the gold-ringed AF-S Nikkor 24mm f1.4G from 2010 is the most expensive of Nikon’s current f1.4 lenses: 1700 EUR. See my Nikon 24/1.4G review.

A relatively common lens aberration is axial (longitudinal, bokeh) CA, which causes non-coinciding focal planes of the various wavelengths of light.There are some minor modifications to the 24 ART in the new FE version that we’ll highlight here, but this is also an instantly familiar lens to anyone who has used any of the Sigm ART series lenses. You can get a detailed, interactive look at the lens in this video: Sigma’s service can change the mount of the lens between Sony’s E-mount and L-mount (at a cost). This is a unique feature that no other manufacturer offers. [++]

So, consider this video a “ First Impressions” rather than a full review, but the basics are here. Angle of View I would say that the target market for this lens is more wedding or event shooters who need a strong center performance at F1.4. Sigma 24 ART Rendering

Choices, Choices

The adjusted incident angle of the light source from the surface of the first lens as well as the optimised positioning of each aspherical glass element to power layout at respective positions minimise distortion throughout the entire image. High Peripheral Brightness As of review time, Sigma does not publish extension tube specs or manufacture these items, but third-party Sony-compatible extension tubes are available.

Price: The Sigma costs around 750 EUR (incl. 19% VAT) which is not cheap but a fair price for the ambition Sigma has for this lens. The AF-S 24/1.4G ED Nikkor for example costs more than double that at around 1700 EUR. But the manual focus Samyang is even cheaper than the Sigma at around 550 EUR. [+] Normal is for the scene to change size in the frame (sometimes significantly) as the focus is pulled from one extent to the other. As you start watching the video you may notice that the details on the Sigma side of the resolution comparison are a little larger than those on the Sony side, and that the edges seem to be slightly cropped. Matthew Gore | Light And Matter Angle of view comparison of a shot from the Sony lens and the Sigma. Notice that when the Sigma lens was attached, the weight caused the tripod head to sag, so the change is greater at the top of the image than the sides. Ultimately, both lenses are optically excellent, especially in the center of the frame, but the Sony maintains an advantage in resolution and sharpness away from the center of the image at f/1.4 and f/2, and in the corners (probably) until f/5.6. As usual I’ll have a look at the technical data first. I’ve rated the features with a [+] (or [++]), when it’s better than average or even state of the art, a [0] if it’s standard or just average, and [-] if there’s a disadvantage.Like other models in the I series, Sigma supplies not one but two lens caps, so as well as the usual spring-loaded plastic cap, there’s an additional metal disc which attaches magnetically, with a satisfying snap and the magnet feels strong enough to keep it in place too. With the hood mounted though, this second cap is a little awkward to fit or remove, so it’s arguably a bit of a novelty, but I like that Sigma’s trying something different here. Made in Japan, each Art lens is tested with Sigma's proprietary MTF measuring system, ensuring a quality product. This is a rather solid petal-shaped plastic hood with a ribbed interior designed to avoid reflections. Above left: Nikon AF-S 24/1.4G ED, middle: Sigma Art AF 24/1.4 DG HSM, right: Samyang 24/1.4 ED AS UMC