Sony FE 20mm F1.8 G review
Is this the fast wideangle prime Sony users have been waiting for? Michael Topham paired it with the Sony A7R IV to nd out if it’s worth the money
In the space of seven years, since the arrival of the first A7-series cameras, Sony has established a healthy range of full-frame lenses for its mirrorless system. There are many exemplary examples among the 31 full-frame E-mount lenses Sony currently offers and in recent years we’ve witnessed Sony focus efforts on increasing the number of telephoto lenses for the serious enthusiast and working professional. Having delivered some of the requests photographers have made, Sony has started to look at other areas of its lineup where lenses are missing. The number of fast wideangle primes is one such area where there’s been a shortage.
As impressive as Sony’s FE 24mm F1.4 G Master (£1,295) is, it’s on the expensive side and doesn’t provide the wide field of view many photographers specialising in architectural, landscape and astro photography are after. This has forced many to buy a fast wideangle zoom instead, or consider a third-party prime alternative. Examples of the latter that benefit from autofocus include the Tamron 20mm F/2.8 Di III OSD Macro (£399), Sigma 20mm F1.4 DG HSM (£669), Samyang 18mm F2.8 FE AF (£259), Tokina FíRIN 20mm F2 FE AF (£799), and Zeiss Batis 18mm F2.8 (£949). Another interesting option is the manualfocus Laowa 15mm f/2 FE Zero-D, which costs £829.
After acknowledging it was about time to produce a fast wideangle prime of its own, Sony set about making the FE 20mm F1.8 G. Designed to be a compact lens promising excellent edge-toedge sharpness and reliability for a wide variety of shooting requirements, it fills a missing gap in Sony’s lineup and
becomes the widest and fastest fixed focal length lens from the manufacturer to date.
Although the FE 20mm F1.8G sports the letter ‘G’ on its barrel, it should be pointed out we’re not looking at a Sony G Master lens. Those familiar with Sony’s top- of-the-line G Master lenses, which are known for their optical excellence and exceedingly high prices, will know how to tell them apart from their G-series counterparts. The clue is in the red background to the letter ‘G’ on the barrel, which differs to the G-series lens we’re looking at, which has a black background. Subtle differences in branding aside, the lens features a complex optical design made up of 14 elements in 12 groups. This arrangement includes two advanced aspherical (AA) lens elements to provide highperformance from corner-tocorner at wide apertures and help mitigate sagittal flare – a common phenomenon with fast wideangle lenses where points of light, such as stars in the night sky, appear as if they’re spreading at the periphery of the frame. To counteract the effects of chromatic aberration the lens also employs three extra-low dispersion glass elements, two of which are located towards the centre of the optical configuration, with the other positioned just behind the front element. Not forgetting the importance of ensuring out of focus points of light are rendered smooth and circular, the lens also benefits from nine rounded aperture blades. These are clearly obvious when you remove the lens and inspect it from the rear.
To maximise the speed of autofocus and ensure it’s well matched with the high-speed capabilities of Sony’s latest A7-series cameras, the lens is equipped with two extreme dynamic (XD) linear motors. These are developed to deliver higher thrust and efficiency, working in tandem with new control algorithms, to drive the lens’s large focus group in a smooth and silent manner. In AF mode users can exploit the lens’s 19cm minimum focus distance, which reduces to 18cm if you’re prepared to focus manually. To help suppress reflections that can cause flare and ghosting the lens benefits from Sony’s original Nano AR coating, with the front element also gaining a fluorine coating that repels water and makes it easy to wipe off fingerprints or other contaminants.
Thanks to its internal focusing, the 67mm filter thread at the front of the lens doesn’t rotate – good news for regular users of polarising filters who don’t want to be forever readjusting them between shots. A plastic petal-shaped, bayonet hood is also supplied in the box along with front and rear caps and a soft lens case. While the lens is most likely to see use with Sony full-frame cameras, there’s nothing to prevent owners of Sony’s APS- C E-mount cameras using it. Paired with cameras like Sony Alpha 6100 or Alpha 6600, it offers an angle of view equivalent to a 30mm lens on full frame.
Small but mighty
Compared to the Sigma 20mm F1.4 DG HSM, the FE 20mm F1.8G is much more compact and balances brilliantly with A7-series bodies like the Alpha 7R IV, which has a new and improved handgrip over older models. There’s no hint of the lens making the camera feel nose heavy like there is with some big wideangle zooms and you get a brilliantly designed aperture ring that gives you the choice of it notching into position at 1/3EV intervals, or the option of engaging a ‘click off’ setting that turns it into continuously smooth aperture ring for silent aperture control during movie recording. At the far end of the aperture scale the lens can be set to ‘A’. This hands aperture control back to the camera’s front dial if you prefer to work in this way.
Just above the AF/MF switch, Sony has added a focus hold button. Enter the Custom Key settings from the camera’s menu and you can reassign it from a variety of different settings. Something I did observe about this button in use though is that it does click fairly loudly and isn’t as quiet as many of the buttons on the A7R IV’s body. As for the manual focus ring, this is rubberised, which helps differentiate the feel between it and the thinner aperture ring from behind the camera. It’s as smooth as manual focus rings get and its linear response provides incredibly precise control. Although not guaranteed to be 100% dust and moisture proof, the lens has seals at strategic points in its construction to ensure reliable operation in all but the most harsh and demanding of environments.
Performance
The image quality performance is best described as sublime. Using it with Sony’s 61-million-pixel A7R IV gave it as stiff a test as it could get and even when it was paired with this powerhouse, it delivered exceedingly impressive results through its aperture range. The lens resolves highly respectable sharpness in the centre of the frame wide- open at f/1.8, with only marginally softer corners, with the opening shot to this review being a good example. This is great news for astronomy and nightscape photographers who are likely to use the lens close to its maximum aperture in complete darkness. Stopping down to f/2.8 sees centre and corner sharpen up more with a gradual increase in sharpness across the frame to its so- called ‘sweet spot’ in the aperture range, which I identified at around f/5.6.
The introduction of diffraction softening detail was observed when aperture settings of f/16 and f/22 were used, so it’s best to avoid these if you want to be rewarded with the sharpest shots.
With chromatic aberration and distortion compensation turned on from the lens compensation menu in the camera, the built-in lens profile that’s applied automatically to raw files did a fine job of correcting these optical flaws to the extent no fringes of colour or obvious bowing of straight lines were visible in my real-world images. The way I look at it, there’s little, if any reason, to ever need to turn these lens compensation aids off. As for shading correction, this is also accessed via the lens compensation options in- camera. This effectively curtails, but doesn’t completely remove the vignetting at the far corners at f/1.8. Stop down to f/2 and f/2.8 and you’ll notice vignetting is quick to disappear, with no trace whatsoever at f/4 or beyond. Overall, it’s an extremely impressive performance from such a small and lightweight wideangle prime.
‘ The lens has seals at strategic points in its construction to ensure reliable operation’