Tag Archives: Astro

Sony FE 20mm f / 1.8G lens test: an excellent landscape lens

"With maximum sharpness and minimal distortion, the 20 mm lens from Sony is an almost perfect astrophotography and landscape lens."

• Outstanding sharpness

• Small to no aberrations

• Light

• Aperture de-click switch

• Weatherproof

• Slight barrel distortion and vignetting

With the exception of third-party manufacturers, the Sony FE 20mm f / 1.8G is the widest full-frame E-mount prime lens to date. It's designed to take more of the scene and offers a 94-degree angle of view – phone photographers can imagine it is between the wide-angle and ultra-wide-angle lenses of an iPhone 11 – but adjusts this field of view with a large f / 1 , 8 aperture for excellent low-light performance.

While the focal length and aperture are clear in the name of the lens, other features from Sony such as the "advanced optical design" and the "Dual XD Linear Motor" have to be decoded. (I'll come to that.)

But are these features worth nearly $ 900? Thanks to superior sharpness and minimal distortion, I have to say yes. This is still a niche lens, but its jargon-packed list of features is more than just marketing hype.

Design and specifications

The FE 20mm f / 1.8 is part of Sony's high-end G-series (but not the high-end GM-series) and is housed in a weatherproof, lightweight housing that fits on the A7R IV which I served as a test camera, this review felt at home. These two linear autofocus motors help the lens adjust the performance of modern Alpha series housings, while a dedicated aperture ring with a click switch enhances its appeal for serious video shooters.

The lens feels sturdy and well built. The barrel isn't made of metal, but that helps keep the weight at a reasonable 13 ounces. With a length of 3.5 inches, it doesn't take up much space in the camera bag and accepts modest 67mm filters.

What is not obvious when looking at the lens is the optical design, which consists of 14 elements in 12 groups with an aperture of nine wings that stops up to 1:22.

An aperture ring offers direct control of the aperture without having to rely on a camera-based dial. This takes getting used to, but feels just like how you naturally hold a camera in two hands.

The aperture ring is not just about ergonomics. With the de-click switch, the aperture settings can be adjusted silently and continuously, which is important for video recording. I definitely prefer to enable the click for still images as you can feel how much you've adjusted it without looking. (The aperture value is still displayed in the electronic viewfinder, but the click only feels more reassuring.)

In addition to the aperture ring and the de-click switch, there is a focus lock button and a switch in the lens barrel with which you can easily switch from auto focus to manual mode. A standard focus ring is located on the front of the lens.

Autofocus

This is where the dual XD linear motor system comes in, which is said to generate fast and quiet auto focus. My experience matched these claims. The auto focus is pretty quiet. It is not silent, but it does not distract you when you take pictures in a sensitive environment such as a wedding ceremony.

The speed of the autofocus was in line with the expectations we had of the A7R IV – fast and accurate, only struggling with subjects that most cameras struggle with, such as shiny objects or where there is not much contrast.

The 20 mm focus very close to the front of the lens, about 7 inches. With the large focal length, this is not enough for real macro functions, but I did not expect the generous 0.2x magnification. For a wide-angle lens, this close-up opens up a number of creative possibilities for a variety of subjects.

picture quality

Note that 20 mm is an unusual focal length – 24 mm is much more common for a prime number, since larger angles are usually covered by zooms, e.g. B. the FE 16-35 mm f / 2.8 from Sony. The focal length is ideal not only for taking wide views, but also for exaggerating the distance between objects, while the bright aperture of 1: 1.8 simply cannot be achieved by zooming.

The lens has some barrel distortion towards the edges, but less than expected with a wide-angle lens. Lines near the edges of the frame are gently curved towards the corners, but this can easily be attached to the post.

Vignetting is also a common problem with wide-angle lenses, especially with such large apertures, but the Sony 20mm only had a very slight darkening in the corners. The vignette was completely removed by a slight adjustment of +5 in Lightroom.

However, the resolution is even more impressive. The sharpness was excellent in the middle, even wide open, and really showed what the 61 megapixel A7R IV can do. Lowering the aperture brought a slight improvement, but if you want that dreamy, shallow depth of field, you don't have to worry about sacrificing focus to get it. The edges had only a slight drop in sharpness, which is probably not recognizable in real pictures.

Where the lens really shines is in astrophotography. This is certainly a photographic discipline in which both bright apertures and wide angles are required and where sharpness is of the utmost importance. Stars are represented as tiny pinpricks of light without sagittal coma flickering, even towards the edges of the frame. Together with the resolution of the A7R IV, the lens helped capture an abundance of sharp stars.

Small light sources do not suffer from the usual flares, while larger light sources – such as the sun or the moon – create starbursts. But the flare is well controlled overall in the FE 20 mm, and even hard light didn't cause much of a problem. Occasionally, a starburst was paired with a rainbow arch or a slight color shift, but nothing big. Chromatic aberration also does not appear to be present.

Wide angles are generally not thought of for their bokeh, but the FE 20mm f / 1.8 looks great here. With an aperture of nine sheets, even a stopped recording creates soft, circular blur patterns. I couldn't see any "onion rings" or other strange shapes that bokeh fans like to criticize.

For videos, the lens produced more of the same with sharp details and well-controlled stray light. The clicked aperture is very impressive here; I could hear my own breathing, but no mechanical noise when I set the aperture while recording.

Our opinion

The wide angle, the fast aperture and the high-end optics ensure an excellent mix of the Sony FE 20mm f / 1.8G. The sharpness is excellent, aberrations are minimal or nonexistent and all the things that wide-angle lenses do most struggle – like barrel distortion and vignetting – are minor and barely noticeable on most shots.

For $ 898, this is certainly not a budget prime. But for photographers who regularly pull out a wide angle, the high-quality workmanship and the impressive optics are probably worth it. The lens is ideal for astrophotography, landscapes and any other picture that needs a broad perspective.

Is there a better alternative?

The focal length of 20 mm is not very common, and for e-mount shooters it depends on this Sony that Sigma 20 mm 1: 1.4 DG HSM Art.or just with a zoom.

The Sigma is an excellent lens, but some users complain about corner distortion when shooting stars. Designed as a DSLR lens, it weighs twice as much as the Sony. In addition, there is not the usual financial advantage of a third-party provider, since both lenses cost the same.

However, the Sigma has a brighter aperture of 1: 1.4 for shots where the last bit of light is important. The Sony 20mm is probably the better option for most, as the 1: 1.4 advantage over 1: 1.8 is pretty small, but the size and weight difference is big.

How long it will take?

The Sony 20mm is well built, so the lens should last for several years, apart from a major disaster. Lenses typically have long product lifecycles, so we wouldn't expect a replacement for many years.

Should you buy it

Yes. If you need a bright wide-angle prime in your kit, the Sony FE 20mm f / 1.8G offers excellent quality in a light, durable lens that's not too expensive.

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