Hands-on with the Sony FE 14mm F1.8 GM
Sony has just announced the impressively small FE 14mm F1.8 GM. The design philosophy behind the lens is simple: offer a super wide field-of-view, a bright aperture, achieve high sharpness across the frame and all-round optical quality at its maximum aperture, and offer it all in a compact and lightweight package. Yes, that makes it sound like it could be the ideal design philosophy for any lens (just swap out ‘super wide’ for your desired field of view) so, jokes aside, does this Sony deliver?
So far, it looks promising. Read on to learn more.
Size and weight
The first thing you’ll notice about the FE 14mm F1.8 GM is just how small it is. Especially if you’re used to the Sigma 14mm F1.8 DG HSM Art optic, pictured on the left. The Sony, at 460g (16.2 oz), weighs just over a pound, while the Sigma at 1230g (43.4 oz) weighs nearly three times as much. The Sigma is also 152mm (6″) in length with a 95.4 mm (3.8″) wide barrel, compared Sony’s 99.8mm (3.9″) long barrel that’s 83mm (3.3″) in diameter.
To be fair, some of that extra heft on the Sigma, particularly the length, is due to the fact that it wasn’t designed natively for mirrorless (Sigma’s mirrorless-only 14-24mm F2.8 DG DN Art is relatively small while exhibiting high optical performance).
The compact, lightweight design of the FE 14mm F1.8 GM makes the lens ideal for drone and gimbal work.
Build quality and sealing
Despite its compact size, the 14mm F1.8 GM lens feels well-built. Similar to other lenses in the GM-series, it’s rated as ‘dust and moisture resistant’, with seals around all buttons and rings. A rubber gasket around the mount should help protect against moisture and other elements entering the camera body.
A fluorine coating on the outer surfaces of both the front and rear elements helps prevent the buildup of fingerprints, oils, dust, water and other contaminants, and also makes it easy to wipe these off should the accumulate on your lens.
And speaking of the outer surfaces, the bulbous front element (and the fixed hood) make the use of screw-on filters impossible, but there’s a slot for sheet filter cutouts on the mount at the rear of the lens (pictured above). Sony provides a template for creating filters of the correct size and shape in the box. This will be useful videographers needing neutral density filters to achieve slower shutter speeds while utilizing the bright apertures this lens affords. This approach rules-out the use of variable ND filters but they tend not to work well with ultra-wide lenses anyway.
The FE 14mm F1.8 GM lens offers a number of external controls. A focus hold button can be customized to any function available to all other custom buttons on the camera body. A focus mode switch allows you to quickly switch between auto and manual focus. When focusing manually, the focus ring offers a linear response for intuitive focus pulls in video and stills. This focus ring has a rubberized texture that makes it easy to grasp and that also differentiates it from the aperture ring.
External controls (continued)
The aperture ring has a texture similar to the lens barrel but with ‘teeth’ to make it easy to grasp and turn. F-stops are marked in 1/3 EV steps. The aperture ring can be ‘clicked’ or ‘de-clicked’, with the latter setting making it easier to smoothly change the aperture if you wish to vary the depth-of-field while shooting video.
Optical design & performance
The optical design comprises 14 elements in 11 groups. One aspherical element and two XA (‘extreme aspherical’) elements effectively minimize sagittal flare, also known as coma. Minimal coma is particularly important for a lens like this one that’s expected to see wide use in astrophotography and nightscape applications. Our initial samples indicate that coma is indeed well-controlled.
Those XA elements also help the 14mm F1.8 GM lens achieve high central and corner to corner sharpness, even wide open. MTF charts (representing a ‘perfect’ instance of the design) indicate that contrast remains at nearly 100% wide open for most of the field, only dipping slightly at the extremes, but still never below roughly 95%. Central sharpness wide open is greater than 90%, remaining well above 80% for most of the frame, and only dimming slightly below 80% at the extremes. Take a look at our aperture series; you’ll note impressive edge-to-edge sharpness even at F1.8.
The front XA element has a downright impressive amount of curvature that help it achieve these optical feats. As per usual with recent GM lenses, high surface precision of molds used to make aspherical elements ensures smooth bokeh without the presence of onion rings or hard edges.
Optical design & performance
The optical design also comprises one ‘super’ ED (extra-low dispersion) and two ED elements to minimize chromatic aberrations. Lateral chromatic aberration simply isn’t an issue: uncorrected we see only 1-2 pixels worth in extreme situations (in full-screen mode, use the loupe to enlarge the white section of building at the left edge of this picture), and corrected it’s hard to spot any residual fringing (see the corrected version of this image here). For perspective, 1 to 2 pixels in a 50MP file translates to 0.2 to 0.4 mm in a 40 x 60 in print.
Longitudinal chromatic aberration, usually a significant issue with some uncorrected fast primes shot wide open, is largely absent: there’s no magenta or green fringing in front of and behind the plane of focus, respectively, at wide apertures.
Optical design & performance
The combination of a wide field-of-view, which renders point light sources rather small, and nine aperture blades makes for pretty 18-ray sunstars. They’re particularly nice with this lens, with sharp, tight rays that don’t diverge or split. The nine aperture blades also ensure a circular aperture as you stop down, meaning that out-of-focus highlights remain circular, and bokeh remains generally smooth and Guassian, even at smaller apertures.
Focus is fully internal. The middle groups of the optical system are driven by two XD (‘extreme dynamic’) linear motors that provide high thrust and efficiency for nearly instantaneous focus. Focus is also silent, with minimal vibration. The combination of fast and silent focus along with quite effective touch tracking, and completely automatic tracking focus modes in video on Sony’s recent cameras make the lens well suited to run-and-gun and drone videography.
The minimum focus distance is 0.25 m (0.82 ft), for a maximum magnification ratio of 0.1x.
Pricing and availability
The Sony FE 14mm F1.8 GM will be available in May for $1600.
What do you think of the Sony FE 14mm F1.8 GM? Is it destined for your gear bag? Let us know in the comments. And if you haven’t checked out our sample gallery yet, be sure to do so to see how the lens performs.
Author: Go to Source