The AF 50mm f1.8 from the Chinese manufacturer Viltrox is a standard prime lens designed for mirrorless cameras and corrected for full-frame sensors. A popular focal length for street photography and general-purpose use, it features a relatively bright f1.8 focal ratio and is one of four prime lenses from Viltrox which can autofocus on Nikon Z-mount cameras – the others being the AF 85mm f1.8 II, AF 35mm f1.8, and AF 24mm f1.8. The lens is also available in Sony E-mount. To my knowledge these are the first – and currently only – third-party lenses for Nikon Z-mount with autofocus – probably exploiting Viltrox’s experience with their Z-mount adapters. The Viltrox AF 50mm f1.8 was announced in December 2021 and costs around 395 EUR / 380 USD / 355 GBP.
For this review I tested the Viltrox AF 50mm f1.8 on the 45MP Nikon Z7 camera to judge optical performance and quality of autofocus against the Nikon Z 50mm f1.8 S. I also included comparisons with the Voigtländer 50mm f2 APO-Lanthar (also available in Sony E-mount) and the Sony FE 50mm f1.8 shot on a 42MP Sony A7R II. So if you’re interested in which “nifty fifty” is right for your Nikon or Sony mirrorless camera, you’ve come to the right place!
Facts and features
As usual I’ll have a look at the technical data of the new Viltrox AF 50mm f1.8 first. I’ve rated the features with a [+] (or [++]), when it’s better than average or even state of the art, a  if it’s standard or just average, and [-] if there’s a disadvantage. For this comparison I use the Nikon Z 50mm f1.8 S (“Z-Nikkor” for short), Sony FE 50mm f1.8 (“Sony FE”), and Voigtländer 50mm f2 APO-Lanthar (“Voigtländer”).
Size (diameter x length): 70 x 90mm (2.8 x 3.5in.). The lens hood adds 38mm and is 78mm in diameter. This is similar to the Z-Nikkor at 76 x 87mm + 40mm lens hood. The Sony FE is only 69 x 60mm + 26mm lens hood, the Voigtländer is 68 x 64mm + 22mm lens hood. 
Weight: 394g (13.8 oz.) plus 28g for the lens hood: The Z-Nikkor is 412g + 27g lens hood, the Sony FE is 166g + 18g lens hood, the Voigtländer is 387g + 19g lens hood. 
Optics: 11 elements (including 3 special dispersion and 2 aspherical) in 10 groups. The Z-Nikkor is a 12/9 design, the Sony FE is 6/5, the Voigtländer 10/8. Viltrox’s marketing material mentions “Nano Multilayer Coating” on their AF 50mm f1.8 to reduce flare, glare and ghosting. [+]
Closest focus distance in manual focus is 0.58m (1.9ft.) with a magnification of 1:10 which is a bit disappointing. The maximum magnification of the Z-Nikkor is 1:6, the Sony FE achieves 1:6.6, the Voigtländer goes to 1:6.4. [-]
Use with teleconverters: None of the lenses in this comparison can be used with teleconverters. 
Filter-thread: 55mm on the Viltrox, the Z-Nikkor has 58mm, the Sony FE 49mm, the Voigtländer 52mm. [+]
Image stabilization: The lenses in this comparison don’t have optical stabilization. You only get the built-in sensor-shift stabilization which most modern mirrorless camera bodies provide. 
Auto focus: Yes with built-in AF drive. Manual-focus override is by simply turning the focus ring (unless you’ve assigned a different task to this mulit-function ring). The focus ring has the usual variable gearing similar to the Z-Nikkor and Sony FE. The Voigtländer is manual focus only. [+]
There’s a type C “USB upgrade port” on the lens mount to update the firmware, see below. The lens came with firmware v1.0.5 which was the latest version at the time of testing. Btw: Their Nikon Z lens mount is not up to specs: When you turn the lens fully to unmount it wont come off – just turn it a bit back to get the lens off the camera body. 
Covers full frame/FX or smaller. Same with the alternatives. [+]
Price: The lens is currently priced at around 395 EUR (incl. 19% VAT) / 380 USD / 355 GBP but I’ve already seen prices as low as 330 EUR. The Z-Nikkor currently goes for about 550 EUR / 500 USD / 500 GBP (with rebates), the Sony is at 180 EUR / 250 USD / 160 GBP, the Voigtländer is at 1099 EUR / 1049 USD / 849 GBP. 
Comes with a soft pouch and the lens hood is included, reversible for transport. That’s similar to the Z-Nikkor. The Sony FE and Voigtländer come without a pouch. 
Aperture ring: The Viltrox, like the Z-Nikkor, has a multi-function control ring which can be assigned by the Nikon Z camera to operate the aperture, exposure compensation, ISO sensitivity, focus – or simply switched off. But on the Viltrox there is also a dedicated aperture ring with 1/3 stops (without clicks) from f1.8 to f16 and a position “A” for aperture control from the camera. The Sony FE has no aperture ring, the Voigtländer has one with 1/3 click-stops. Turning the multi-function control ring on the Viltrox other than in focus mode reveals a much too aggressive gearing: Even small turns of the ring result in large changes in aperture, exposure compensation or ISO. This works much smoother on the Z-Nikkor. [+]
Sealing: No, both the Viltrox and the Voigtländer don’t even have a rubber grommet at the lens-mount. The Z-Nikkor and Sony FE have a rubber grommet at the lens-mount and the Z-Nikkor has further special weather-sealing throughout the construction. [-]
At a score of 2[-]/7/5[+] the lens has no outstanding features – except for the dedicated aperture ring. Its price is a bit lower compared to Nikon Z-Nikkor but the Sony FE is even cheaper. And the Viltrox does not offer basic weather protection at the lens mount plus its maximum magnification of 1:10 is a bit disappointing.
Focus accuracy and repeatability is critical to consistently produce sharp shots especially with large aperture lenses. Repeatability (the accuracy of focus on the same subject after repeated focus-acquisition) of this lens was measured 98.2% in Reikan FoCal – same as the Z-Nikkor. There was only one slight outlier over a series of 40 shots on the well lit and contrasty focus test target. On real-life targets with more normal contrast I had the impression of less consistent focus action.
Regarding focus speed: The Viltrox focuses in around 0.7 sec from infinity to 0.58m (1:10 magnification) – same as the Sony FE, which is a tad slower than the Z-Nikkor (0.5 sec). There was only little hunting under the well-lit test conditions. The focus ring (which also can be assigned other tasks by the Nikon Z camera) is 34mm wide. Its surface is not rubberized and feels a bit too smooth for my liking.
AF-operation of the Viltrox is barely audible from the outside. If you record video with the built-in microphone the AF-drive produces only a low whir. As you pull-focus, you’ll notice pretty little focus breathing: the image became 3-4% more magnified when I adjusted focus from infinity to 0.58m. This is barely visible when shooting videos.
Next check out my quality results!Check prices on the Viltrox AF 50mm f1.8 at B&H or Adorama. Alternatively get yourself a copy of my In Camera book, an official Cameralabs T-shirt or mug, or treat me to a coffee! Thanks!