The Viltrox AF 50mm F2 Air ($199) is a value-priced standard prime lens that doesn't make a lot of sacrifices. The prime is tack sharp at maximum aperture, focuses quickly and quietly, and draws images with pleasingly soft backgrounds. It omits some creature comforts like an aperture control ring and weather sealing, but those are expected compromises given its price and featherweight design. At press time, it is available for Nikon Z and Sony E camera systems and earns our Editors' Choice award for both. We like it more than Nikon's value Z 40mm F2 ($299.95), and it's a better, cheaper take on what Sony tried to do with its FE 50mm F1.8 ($249.99).

Design: The Thrifty Nifty Fifty

The AF 50mm F2 Air is a fresh take on a classic lens type: The low-cost, standard angle prime that was the de facto default starter lens decades ago, prior to the widespread adoption of zoom optics and autofocus. Prime lenses use wide, bright apertures to get clean images in low light and to snap photos with softly defocused backgrounds. The 50mm focal length covers an angle that's somewhere in between wide angle and telephoto, and has proven popular enough to get a nickname: the nifty fifty.

(Credit: Jim Fisher)

Viltrox's take on the concept is small and light (2.2 by 2.6 inches HD, 7.2 ounces) and avoids some of the pitfalls we've seen from first-party attempts to make a nifty fifty that qualifies as thrifty. Autofocus is faster and quieter than the Sony FE 50mm F1.8, for instance, and the lens includes a metal mount, in contrast to the plastic mount Nikon uses for the Nikkor 40mm F2.

That's not to say the AF 50mm F2 Air competes with mid-priced and premium lenses in fit and finish. The Nikkor Z 50mm F1.8 S includes dust and splash protection that's missing from the Air, Sigma's 50mm F2 DG DN Contemporary features an aluminum barrel and aperture ring, and Sony's lux FE 50mm F1.4 GM offers far more on-barrel controls than the Viltrox, plus snappy linear autofocus.

(Credit: Jim Fisher)

The AF 50mm F2 Air houses its 13-element/9-group optical arrangement in a polycarbonate barrel with a black finish. The lens includes front and rear caps, a reversible hood, and is compatible with 58mm threaded filters. It does not include internal weather sealing, but has an anti-smudge fluorine coating on its front glass and also has a USB-C port on its mount for firmware upgrades. Viltrox sells the Air for Nikon Z and Sony E mount cameras, and the optics support full-frame sensors, but the lens also works with APS-C cameras. If you use it with an APS-C body, its angle of view is restricted, so it acts more like a short telephoto (75mm equivalent).

The brand of camera you own plays some part in the 50mm F2 Air's place against competitors. Sony has been making full-frame FE lenses since late 2013, and keeps its E-mount open to third parties, so there's a laundry list of compatible 50mm primes at various price points, but the Viltrox is only undercut in price by one other, the $170 Meike 50mm F1.8. The Meike is also the lowest cost option for Nikon Z, where there are fewer options in the focal length all around. Nikon's most affordable is the $500 Nikkor Z 50mm F1.4, which justifies its price with weather-protected construction and optics that open to catch twice as much light as the 50mm F2 Air.

(Credit: Jim Fisher)

Focus: Quiet, Accurate Autofocus

The AF 50mm F2 Air has only one control surface, a manual focus ring. The ring offers just enough resistance for comfortable operation with no wobble or slop. If you own a Nikon camera, the ring can also be configured to work for aperture, EV, or ISO control when using autofocus, and always reverts to manual focus when you change to that setting in camera.

(Credit: Jim Fisher)

The lens uses a stepping motor (STM) for autofocus, a type often employed in smaller primes and other lenses with lightweight focusing groups. Here, the focus tech proves to be accurate and quiet, but a little slow. If your scene is way out of focus to begin with, the lens takes as long as 0.7 seconds to drive to the proper plane and capture a sharp image.

The lag time is cut significantly if your scene is nearly in focus to start, so you won't have to wait as long to grab a snapshot in most instances. I'd only count the focus speed as a drawback for action scenes where subjects move toward or away from camera. For a lens like this, I'd imagine photos of kids and pets at play are a typical stress test for autofocus. If those are the types of scenes you like to capture, consider stepping up to a lens with snappier focus like the Sigma 50mm F2 Contemporary (for Sony) or the Nikkor Z 50mm F1.8 S.

(Credit: Jim Fisher)

The lens shows very little, if any, focus breathing, which is a positive for creators who want to use it for movies. Lenses that breathe show a change in angle of view when changing focus. Since the 50mm F2 Air avoids the effect, you can use it for rack focus shots that shift attention between two objects and other cinematic narrative techniques that utilize shifts in focus.

(Credit: Jim Fisher)

The 50mm F2 Air has a 20.1-inch minimum focus distance, so you can't use it to get as close to objects as the FE 50mm F1.8 (17.8 inches) or the Nikkor Z 50mm F1.8 S (15.7 inches). The Viltrox 50mm captures subjects at 1:9.1 life-size at its nearest distance, which is well outside the realm of high-magnification macro photography. I got good results using the lens for flower photos at my local conservatory, but you won't be able to hone in to capture textures and tiny details in pollen patterns like you can with a dedicated macro like the FE 50mm F2.8 Macro or Nikkor Z MC 50mm F2.8.

(Credit: Jim Fisher)

Image Quality: Crystal-Clear Images With Colorful Flare

I tested a Z mount copy of the Viltrox AF 50mm F2 Air with the 45MP Nikon Z 8. The lens delivers stellar results on an Imatest lab evaluation, notching excellent resolution numbers (4,400 lines) at f/2 and improving to the outstanding range (4,500-5,000 lines) from f/2.8-11. Impressively, the lens is nearly as sharp at the edges as it is in the center throughout its range.

(Credit: Jim Fisher)

The aperture closes down to f/16, though it loses some resolving power at the minimum setting (4,100 lines) due to optical diffraction, an effect of physics that makes light particles scatter apart as they pass through a narrow diaphragm. Simply put, the 50mm F2 Air is far sharper than any $200 lens has a right to be.

There's more to optical performance than resolution, however. I also look at distortion, vignette, flare, and bokeh quality when testing lenses. The optics show very little distortion, just a hint of the pincushion effect, and slightly darkened corners and edges at f/2-2.8 that draw a natural vignette around a scene. You can use your camera's built-in vignette and distortion correction features to compensate for both when using JPGs, or make manual corrections, or use a lens profile when editing Raw images. I wouldn't worry at all about the distortion, as it's slight to the point that it just barely merits a mention, but you may want to reduce the vignette if you find the effect distracting.

(Credit: Jim Fisher)

The AF 50mm F2 Air shows flare in scenes when the sun or another bright light source hits it directly. I used it for some pet portraits in a sun room with large windows and the setting sun coming in at a low angle, and noted heavy flare with rainbow effects and a soft glow. This is a pretty extreme test case for flare, and in this instance, I found the effects aesthetically pleasing. I also tried flare tests with my iPhone's LED light and noted some faint globs of false color when the light hit the front glass at an oblique angle. All in all, flare resistance is a little less than what we see from Nikon, Sigma, and Sony lenses, but it's easy enough to avoid if you use the hood and play with shifting your camera angle slightly when incorporating the sun or another strong backlight into a scene. 

(Credit: Jim Fisher)

Bokeh quality is of extra concern to photographers choosing a wide-aperture lens. Thankfully, the Viltrox AF 50mm F2 Air delivers pleasingly soft backgrounds with rounded highlights. I see a teensy bit of false texture in bright highlights. This onion skin effect is caused by imperfections in molded aspherical optical elements and is pretty subtle with this lens. 

Defocused highlights are evenly illuminated, a characteristic that leads to softer backgrounds in general. I photographed several scenes with foliage behind the subject, and am happy to see how well the Air avoids the busy character we see from some other Viltrox glass, like the 135mm F1.8 Lab.

(Credit: Jim Fisher)

I couldn't spot any signs of any false color in backgrounds and transitions between focus and blur. That's good news as purple and green longitudinal chromatic aberration that's often visible with bright aperture lenses is all but impossible to remove with software, black-and-white conversions aside.