This is another look at the Viltrox AF 50mm f/1.4 Pro, but this time in Nikon Z mount. Most of the findings are similar, if not identical, to our Sony E-mount review, so we’ll reuse some of the article here. The Z-mount version has a retail price of $549 USD (619EUR / 525GBP / 799CAD / 90400JPY), That’s just slightly more than the slower Nikkor Z 50mm f/1.8 S.
The lens body is made of metal down to the mount. It’s not a small lens, and combined with the tough construction, it is on the heavy side at 800g. Viltrox has also implemented some degree of weather-sealing. The focus ring operates smoothly. It exhibited a rubbery squeak in our sample, though. It also features a de-clickable aperture ring with a nice click action. As you can see below, a deep, petal-shaped lens hood is part of the package.
The lens uses a quick Dual HyperVCM Motor for silent and pretty fast autofocusing. Manual focusing works “by-wire”, as usual. Firmware updates are possible via a USB-C port on the lens mount with the Viltrox app for mobile phones.
| Specifications | |
|---|---|
| Optical construction | 15 elements in 11 groups (1x aspherical, 3x ED, 8x HR) |
| Number of aperture blades | 11 |
| min. focus distance | 0.45m (max magnification: 0.145x) |
| Dimensions | Φ 84.5x111mm |
| Weight | 800g |
| Filter size | φ77mm |
| Hood | barrel-shaped (bayonet mount, supplied) |
| Other features | Aperture ring (de-clickable) Customizable Fn-button Firmware updates via USB-C/Bluetooth Weather-sealing |
Distortions
The lens produces a mild barrel distortion of ~1.1%. While this isn’t negligible, it is usually not disturbing. There is no profile built-in for distortion correction.
Vignetting
The RAW vignetting is typical for a lens in this class. At f/1.4, there’s a quite heavy light falloff of 2 EV (f-stops). As usual, stopping down improves the issue, and it’s down by ~0.8EV (f-stops) at f/2 already. Moderate vignetting is reached at f/2.8, and beyond it, shouldn’t be visible anymore in most scenarios.
Unlike the E-mount version, the 50mm f/1.4 Z does have a correction profile for vignetting. It reduces the light falloff by about 1 f-stop at f/1.4. The vignetting is still visible, but it’s not dramatic. The issue is negligible from f/2 onward in this case already.
Note: The tone curve differs between Nikon and Sony, so the RAW vignetting figures are slightly different.
MTF (resolution) at 45 megapixels
The Viltrox AF 50mm f/1.4 Z Pro produced quite impressive resolution results in our lab. The image center is already excellent at wide-open aperture. The quality in the outer image field isn’t quite as high, but you can still expect good to very good quality here. Stopping down to f/2 doesn’t make a really noticeable difference, but there’s a boost at f/2.8, and more so at f/4. The center is downright outstanding here, and the border quality is excellent. The corners are very good at this setting. The corners still improve a little at f/5.6. Diffraction has a slight impact from f/8. f/11 remains perfectly usable, but you should avoid f/16, as usual.
The centering quality of the tested sample was good. The field curvature is flat.
Please note that the MTF results are not directly comparable across the different systems!
Below is a simplified summary of the formal findings. The chart shows line widths per picture height (LW/PH) which can be taken as a measure of sharpness. If you are keen to know more about the MTF50 figures, you may check out the corresponding Imatest Explanations.
Chromatic Aberrations (CAs)
Lateral CAs are slight at all aperture settings, even without corrective measures. The border CAs hover around an average CA pixel width of 0.7px.
Bokeh
A fast lens isn’t just about sharpness; it’s also about the out-of-focus rendering, aka the bokeh – so let’s take a look.
In the image center, the lens produces clean out-of-focus highlights with a smooth inner disc zone and only slight outlining. It’s worth noting that there is some outlining visible beyond the broader center, though. The lens has 11 aperture blades, which helps with maintaining the circular shape (near the center) up to f/2. The slightly more edgy aperture shape creeps in at f/2.8.
When looking at the rendering of the highlight discs across the image field, we can see a moderate deterioration to a more cat-eye-like shape in the corners. From the midfield, there is also some stronger outlining – this is also visible in the sample gallery. Stopping down to f/2 restores most of the border/corner highlight discs already, and the disc outlining is also mostly gone. The discs are fully restored from f/2.8, which is comparatively “early”.
The blur in the focus transition zone isn’t perfect, but the background blur – shown to the left below – is fairly smooth. The less important foreground blur is a bit “shadowy” and as such, quite nervous.
Bokeh Fringing / LoCA
LoCAs, or bokeh fringing, is a color fringing effect on the Z-axis. It shows up with a purplish tint in front of the focus point and a greenish tint behind – and it’s nearly impossible to fully correct in post.
As you can see below, the Viltrox lens shows significant color fringing at f/1.4, and it’s still very noticeable at f/2. The fringing is significantly improved at f/2.8 and gone from f/4 onward.
What you may also notice when scrolling through the different aperture settings: the focus shifts towards the rear when stopping down. These shifts are caused by RSA (residual spherical aberrations). While this isn’t unusual for fast lenses, you should check your images at very close focus distances (unless you used f/1.4 or a small aperture).
Competition
Nikon has opened the Z-mount to third-party manufacturers. However, as of the time of this review, only Viltrox has released a fast f/1.4 standard prime lens. Nikon has no less than three 50s in its lineup (plus a 50mm f/2.8 macro). There’s the already mentioned Nikkor Z 50mm f/1.8 S – and it’s superb, but obviously slower. Then there’s the Nikkor Z 50mm f/1.4. This is a rather simple classic design, and as such, not really comparable. Finally, there’s the Nikkor Z 50mm f/1.2 S, which is in a price and speed league of its own.
Sample Images
The Viltrox AF 50mm f/1.4 Z Pro confirms what we've already seen in the E-mount version of this lens. It's impressive, but it has its flaws. In terms of sharpness, there isn't really anything to complain about. The center performance is great. At large apertures, the outer image field isn't quite as high but still very usable. When stopped down to medium apertures, the quality is very good across the image field. Image distortions and lateral CAs are low. The vignetting is about typical for such a lens. The quality of the bokeh is generally good with a few caveats. Not ideal are axial CAs at large apertures as well as the observed focus shift at close focus distances.
We have (almost) nothing but praise for the build quality. The lens feels like a tank - but it is also about as heavy. The handling of the control rings is superb. The AF 50mm f/1.4 Z Pro is also weather-sealed, and the upgraded AF motor is surprisingly fast.
In summary, the Viltrox AF 50mm f/1.4 Z Pro strikes a nice balance between speed and price.
Viltrox lenses are available via the Viltrox Webstore (5% off for 5 days after the release of this review) or the usual suspects such as B&H or Amazon
The Good
- It's sharp
- Great build quality
The Bad
- Strong focus shifts at close focus distances
- It's heavy
- You have to stop down a little for a smoother bokeh
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Optical Quality
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Build Quality
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Price / Performance