Viltrox AF 16mm f/1.8 Review

Viltrox AF 16mm f/1.8 Focusing Characteristics

The Viltrox AF 16mm f/1.8 uses a stepping motor to focus, and while it definitely isn’t the fastest lens on the market, it was fast enough to be unobtrusive. I had no issues with the lens’s autofocus accuracy or consistency, either. I wouldn’t say that the autofocus performance was quite as seamless as on the Nikon Z 20mm f/1.8 S or Sony 14mm f/1.8 GM, but it was close enough. I’m also encouraged by the USB-C port on the lens – with it, any autofocus malfunctions on future cameras should be fixable via a firmware update.

As for manual focus, like most of today’s lenses, the Viltrox 16mm f/1.8 uses a focus-by-wire system. The focus throw is pretty generous, going from near to far with a little more than half of a rotation. And I didn’t see any substantial lag or imprecision that you might find on some cheaper focus-by-wire systems.

Lastly, in terms of close focus capabilities, this definitely isn’t a macro lens. The maximum magnification of 1:10 is barely enough even for large close-up subjects. If you want to do ultra-wide close-ups, the Laowa 15mm f/4 Macro is still the most obvious game in town. Though interestingly, the bokeh on the Viltrox AF 16mm f/1.8 isn’t bad, in the rare cases that the background is out of focus.

Distortion

The Viltrox AF 16mm f/1.8 has surprisingly low levels of distortion. Granted, prime lenses tend to have much lower distortion than zooms, but ultra-wide primes can be an exception. For example, the Canon RF 16mm f/2.8 is practically a fisheye! But on the Viltrox 16mm f/1.8, I measure just -1.10% barrel distortion in the lab.

Although this amount is small enough not to matter most of the time, I will mention that distortion correction is not widely supported with this lens, unlike first-party glass. The good news is that Adobe Lightroom has a distortion profile for the Viltrox AF 16mm f/1.8, but a lot of other software does not. You may find yourself correcting distortion manually if you use anything other than Lightroom.

Vignetting

In uncorrected images, the Viltrox 16mm f/1.8 AF has pretty high levels of vignetting. The vignetting is worst at f/1.8, and it’s about the same at close focus and infinity. As you stop down to f/4, the vignetting improves, although it hits a plateau and doesn’t get any better after f/4. Here’s what I measure in the lab:

This is definitely on the high side, and it never really gets to negligible levels. You may find yourself needing to correct vignetting in post-processing even when shooting at narrower apertures like f/11.

Chromatic Aberration

There is a pretty low amount of chromatic aberration on the Viltrox 16mm AF f/1.8, although somewhat unusually, I found that it climbed from negligible to moderate levels as you stop down. Here’s the chart as measured in the lab:

The chromatic aberration performance at f/1.8 is downright excellent, although from f/4 to f/16, it does get a little higher. Still, it never reaches crazy levels – in our lab tests, chromatic aberration is considered negligible as long as it measures less than 1.0 pixels. No, the Viltrox AF 16mm f/1.8 does not stay under this level at every aperture, but it never reaches high enough to be concerning. In real-world images, I didn’t find any significant CA regardless of aperture.

Sharpness

The Viltrox 16mm f/1.8 AF is surprisingly sharp and definitely outperformed my expectations. Here’s how it performs in the lab:

The central performance of this lens is some of the best we’ve ever seen, and literally off the charts at f/2.8. Midframe and corner performance is a little more down-to-earth, but still great. This sharpness performance would fit in with Nikon S-series or Sony GM lenses any day. You’ll see that a little more on the next page of this review, Lens Comparisons.

As for other sharpness issues, I found very minimal focus shift or field curvature on this lens. All told, the Viltrox AF 16mm f/1.8 is a great performer – more than sharp enough for any genre of photography that you throw at it. Definitely a surprise to me, but a welcome one!

Coma

Related to sharpness is coma, a lens aberration that can make dots of light in the corner of a photo look like smears. Coma isn’t usually visible in everyday photography, but for something like Milky Way photography, it can be a factor. Given that a 16mm f/1.8 lens is an excellent choice for Milky Way photography, I was really looking forward to testing the coma on this lens.

The crop shown below the following image is taken from the top-right corner of the Nikon Z7 with the Viltrox 16mm f/1.8. I cropped the Nikon Z7’s 45-megapixel sensor down to a tiny 1380 × 920 pixel image and didn’t do any resizing; it is a direct excerpt from the image with Lightroom’s default sharpening and noise reduction applied.

There is hardly any coma here at all! Only the brightest couple of stars have a hint of coma – an excellent performance by the Viltrox AF 16mm f/1.8.

Flare and Sunstars

Complex lenses like this one (15 elements in 12 groups) can be prone to flare if the manufacturer uses subpar coatings. On the Viltrox AF 16mm f/1.8, however, I found essentially zero flare even when the sun was directly in the frame. The lens retained high levels of contrast and also produced some nice good sunstars. You can see that from the images below:

There was just one issue that I noticed where flare was concerned. In rare cases, when the sun was right outside the frame in the perfect (or imperfect?) spot, you would see a long line of flare shine across the image:

This effect only appeared in a small number of my photos taken at narrow apertures, and only when the sun was right outside the frame. Although it’s definitely a negative when it appears, I still consider this to be a strong performance overall where flare and sunstars are concerned.

The next page of this review dives into the sharpness numbers a bit more, with some comparisons against other lenses that you users may be considering. So, click the menu below to go to “Lens Comparisons”: