The Sigma 14mm F1.8 DG HSM Art ($1,599) is a lens that has a lot of appeal for photographers working in certain disciplines—notably astrophotography—thanks to its ultra-wide field of view and bright aperture. Its f/1.8 aperture design will allow you to focus in low light conditions, making it easier for nightscapes and stars. Although it is not as versatile as the Sigma 12-24mm F4 DG HDSM Art lens, this lens can be used for all kinds of photography. However, the prime 14mm will work well if you need a larger aperture.
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Design
It is large. The Amazon 14mm F1.8 costs $1,445.39 The F1.8 measures 5.0x3.8inches (HD) and is 2.5 pounds. It has a large and bulbous front element that allows for images to be captured with a bright aperture and wide field of vision. You can only use it without an accessory holder. Sigma includes both a slip-on lens cap and an integrated lens hood. A soft carrying case and a rear cap are also included.
The construction is strong and consistent with Global Vision Sigma lenses. While the barrel has a metal base, its bulk is made of polycarbonate. It's not cheap plastic, though—it feels very well made. Sigma claims that the lens is protected against dust and splashes. This is important because it will be used a lot for landscape photography.
It is very likely that the front element will pick up fingerprints from time to other. It has a fluorine-based front coating that repels oil and water. This makes it easy to maintain and clean.
You can buy the lens in several mounts—Canon EF, Nikon F, Leica/Panasonic/Sigma L, Sigma SA, and Sony E. There are a few differences between them. It uses the same electromagnetic aperture design as older Nikkor lenses, which means it will not work with any Nikon DSLRs. Only the Canon model can be used with the optional rear filter holder (FHR-11) which costs $36. To install the FHR-11, you will need to feel comfortable using a screwdriver. The versions for mirrorless cameras can be a little longer than those of SLR, which is necessary to keep the distance between the image sensor and the lens element the same.
The wide rubberized manual-focus ring is located at the bottom of the lens cover, in the middle of the barrel. It houses the only control switch: an AF/MF toggle and the focus distance scale. The portion that is narrower holds it. The depth of field marks for f/4 to f/11 and f/16 are located on the lower portion.
You can focus the 14mm lens as close to 10.6 inches from your image sensor. You can get up close and personal with your subject. Although the macro magnification is only 1:9.8, it is due to the wide field of view.
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Image quality
The 14mm F1.8 was tested with the Canon EOS 5DSR 50MP. This camera delivers sharpness even when wide open. It scored 2,963 lines in a center-weighted test at f/1.8, which is better than our minimum of 2,750. However, it's far from an equal field. Imatest indicates that our center is very good (3,870 line), but that it gives way in the middle and edges are slightly soft (2,250 line) during lab tests.
These numbers are a little too low for me. Although the edges look great in field shots at f/1.8 they are not as sharp as the center. Ultra-wide lenses can cause field curvature, so we must place them close to the test chart to be able to frame it.
The lab results at f/2 are similar. The average score is 3,149 lines at f/2.8, which shows an increase in the center resolution (-4180 lines). The edge score at f/4 improves dramatically (2,981 line), and the center area (5.575 line), giving a center-weighted average 4,143 lines. This is a much sharper result than what you can get using the 12-24mm zoom at 12,mm f/4 (3.295 lines).
Peak image quality is achieved at f/5.6 (42,620 lines) or f/8 (5,668 lines), respectively, with edges showing approximately 3,500 lines and 4,000 lines. These are exceptional numbers, particularly considering that the lens is ultra-wide.
Diffraction reduces resolution at two of the most narrow options, f/11 (3.835 lines) or f/16 (3.336 lines), however they are still usable options even with a high-resolution sensor like the 5DSR. Sensors that have lower resolutions may be less susceptible to the effects.
The distortion is approximately 4.3 percent. This is not too much for an ultrawide lens, but it will be a problem if you want the image to accurately reflect reality. The profile in Lightroom offers one-click corrections. However, any editor with a distortion control slider can do the job.
Wide apertures can also cause dimming at the corners. At f/1.8, there is a 4 stop (-4EV) decrease in the center of the frame from corner to corner. This drops to -2.5EV for f/2.8 and -2EV for f/4 and to -1.5EV when shooting at narrow apertures. It won't be noticeable for shots taken at f/5.6 or smaller. However, if the vignette is distracting from wide-aperture photos, you can dial in some adjustment in your software. This will require you to use Lightroom, or any other editing software, since in-camera adjustments are not available for third party lenses.
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Conclusions
While ultra-wide lenses may not be necessary for all photographers, they are essential for certain disciplines. Zooms that are at the upper end of the coverage spectrum I recommend, because they can be used to cover a greater range of subjects and allow you to use the same lens for multiple purposes. However, wide zooms can be f/2.8 and f/4 models. Sometimes you may need to have more light.
For landscape photographers looking to capture night skies and use the Sigma 14mm F1.8 DG HSM Art lens, this lens is a great choice. It's easier to focus manually with a sharper lens with a live view and a better quality than with a duller one. Unfortunately, New York's heavy light pollution meant that the lens was not able to be used for any serious astro photography during my review.
This is a great option for architects photographers who often need quick work and aren't able to use tripods. Bright apertures allow you to capture crisp handheld images with a lower ISO than f/4 zooms like the Sigma 12-24mm ($1,276.21 on Amazon) (Opens in a new browser) and Canon EF11-24mm f/4L USM. These zooms were Editors Choice Winners, but we prefer the 12-24mm due its lower price. The 14mm lens is an option if you need a more powerful zoom.
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