Viltrox AF 9mm F2.8 AIR Review

Viltrox’s AIR series has become one of the most fascinating lineups in the lens market today. Not because they are fancy (they aren’t) or feature rich (ditto), but because they are small, light, inexpensive, and, most importantly, optically impressive. While the earlier lenses in the series tended to fall into the traditional categories (35, 50, & 85mm and their APS-C equivalents), we’ve started to see a few more unique options arriving. Most recently that was in the form of the 15mm F1.7 lens for APS-C. This time, however, Viltrox is doing something a little different – they are releasing full frame and APS-C equivalent versions of a lens on the same day. We have the lens we are reviewing today – the Viltrox AF 9mm F2.8 AIR for APS-C – but also the 14mm F4 AIR for full frame cameras, which I reviewed here. Multiply that 9mm by the 1.5x crop factor and you have a 13.5mm lens (113.8° angle of view vs 112° for the 14mm lens), and the F2.8 aperture helps to compensate for the smaller sensor as well. That’s not to say that these are the same lens, but they clearly share some commonality of design. I’m not sure that I’ve seen something like this done before, but the end result in both cases is quite compelling. It is extremely rare to get a reasonably fast APS-C prime wider than 10mm, particularly in such a compact, inexpensive package (the price is about $200 USD, though you can save 5% off that by using the code “DUSTINABBOTT” at the Viltrox store). Is this the wide angle prime to buy for your Sony, Nikon, or Fuji APS-C camera? Find out my thoughts by watching the video review below or reading on in the text review.

Thanks to Viltrox for sending me a review loaner of this lens. As always, this is a completely independent review. *The tests and most of the photos that I share as a part of my review cycle have been done with the Sony a7RV and the Sony Alpha 1. You can find the product listing page for the Viltrox AF 9mm F2.8 AIR here.

__________________________________________________________________________________________________

Viltrox AIR Series Reviews:

__________________________________________________________________________________________________

AI SUMMARY: The Viltrox AIR 9mm F2.8 APS-C lens stands out as the widest and most affordable ultra-wide prime in Viltrox’s lineup, offering an impressive 113.8° angle of view in a compact package. It delivers sharp, high-contrast images across the frame, with minimal distortion and chromatic aberrations, making it suitable for a variety of photography genres including landscape, architecture, and astrophotography. Its sturdy build, lightweight design, and fast autofocus make it particularly attractive for vlogging, gimbal work, and on-the-go shooting. Overall, the lens provides excellent optical performance at a budget-friendly price, with some minor limitations like lack of weather sealing and busy bokeh.

Strengths:

Extremely wide angle of view and compact, lightweight design
Excellent sharpness, contrast, and minimal distortions across the frame
Fast, quiet autofocus with good video capabilities
Affordable price point (~$200 USD) with solid build quality

Weaknesses:

No weather sealing or advanced weatherproof features
Bokeh can be busy and outlining around highlights may be noticeable
Slight variation and inconsistency in magnification values during testing
Moderate vignetting and distortion that may require correction in post-processing

__________________________________________________________________________________________________

This is not only the widest focal length we’ve seen in the AIR series, it is the widest lens that we’ve seen from Viltrox, period. We are getting right under a 114° angle of view, which is extremely wide for such a compact lens. You can see that the framing of the 9mm is significantly wider than the full frame 14mm lens.

Like it’s full frame brother, the AIR 9mm is capable of producing highly detailed results despite its diminutive size and value price.

Getting such a compete wide angle prime in such a small, inexpensive package has the potential to make for a lot of happy customers. Let’s explore whether or not you should consider this lens for your own kit.

Build and Handling

The theme for the AIR series is “Carry Less, Capture More”. Sometimes Chinese expressions get lost in translation to English, but I think this one works. The key attribute of the AIR series that makes me personally want them in my kit is how easy they are to throw into the bag and bring along while knowing that I’m still going to get great optical results. Initially I was far more excited by the notion of their PRO and LAB series of higher end lenses, but Viltrox has won me over with just how good these AIR lenses are. Both the 9mm and 14mm AIR series lenses look like twins…and both are equally easy to bring along.

The build quality of the AIR series is basic but tough. There is a metal lens mount complete with a USB-C port for easy updates and then an engineered plastic outer shell. The firmware update process is very simple; just unzip the upgrade folder, drag the firmware update file to the folder that shows up when the lens is attached to the computer, and the update is done in seconds.

Viltrox has generally been very good to support their lenses with firmware, though I suspect lenses like the AIR series won’t need many. Viltrox seems to have really perfected this formula, and they aren’t experimenting with new technologies in the way they are with the Pro or LAB series.

Those plastics feel very tough and well made. I’ve had the earliest AIR series lens (the 20mm F2.8) since its release several years ago, and it has held up very well. I never recommend dropping lenses for obvious reasons, but these AIR lenses have been tough enough to handle some knocks.

This is an extremely compact lens, measuring 65mm (2.55″) in diameter and just 56.4mm (2.22″) in length. This is literally the exact same size as the full frame 14mm F4 in both details. This is a small enough lens to easily match the smallest of Sony’s camera bodies.

The front filter size is 58mm, making filter sharing easy across other lenses (including several of the AIR series lenses).

The lens weighs in at 175g (6.17oz) in E-mount and Fuji X-mount form and 190g in Nikon Z-mount due to the larger diameter of Z-mount. That makes the AIR 9mm very slightly heavier (+5g) than the full frame AIR 14mm (most likely due to that lens’ smaller maximum aperture).

It seems like Viltrox has switched from the more confusion sensor dimensions they previously had on their lenses to just including the term “full frame” or APS-C on the lens’ facade instead. I’m not quite sure why most lens makers seem to have a need to come up for some euphemism for APS-C rather than just coming out and saying it.

There is an included lens hood made in high quality, thick plastics. It bayonets into place precisely and stays locked there.

A lens pouch is also included. The pouch doesn’t add a lot of protection value, but, like the hood, at least it is included. There are many more expensive lenses that include neither a pouch or a hood.

There is no manual aperture ring or any swtiches on the lens barrel. The only feature on the lens barrel is a wide manual focus ring. The manual focus ring has a nice amount of damping and moves smoothly. All manual focus aids (including automatic magnification of the focus area) will work with the Viltrox, and I appreciate the fact that manual focus speed is improved to where you can make larger focus changes with one twist of the wrist, particularly if you move faster (this is a non-linear focus ring). The manual focus experience on Sony is good.

The Viltrox AIR 9mm has 7 blades in its aperture iris. You won’t have a lot of situations where you can achieve round specular highlights stopped down with such a wide lens, so more important is the fact that achieve a decent looking 14 bladed sunstar.

This sunstar is a little cleaner to my eye on the full frame 14mm lens than the one you can achieve with the 9mm F2.8 as the blades aren’t as clearly defined on the APS-C lens.

There’s a bit of a quirk with the listed minimum focus distance. On paper, the AIR 9mm can focus as closely as 13cm and should achieve a maximum magnification of 0.15x there. That figure (as with many APS-C figures) is a bit confusing, as companies can list the actual figure (like here) or the full frame equivalent. Just as the 9mm focal length must be multiplied by the crop factor of the camera it is mounted on (1.5x), the same applies to the maximum magnification figure. If you multiply the 0.15x by 1.5x, you get 0.225x, or roughly the 0.23x listed for the full frame 14mm lens. Here’s where things get strange, though, as I was able to achieve a clearly higher level of magnification with the 9mm than the 14mm.

How do I explain this? I don’t know, for certain, though I do find with some lenses that I’m able to get closer using manual focus (my process for testing maximum magnification to ensure I’m accurately getting the highest possible magnification) than what autofocus might allow, and thus achieve a higher level of magnification. What’s clear, however, is that you can get a very high level of magnification out of this lens, and, if you manually focus, it delivers what looks like more of a 0.30x level magnification (full frame equivalent).

While the plane of focus is not perfectly flat at this very close focus distance, the detail and contrast remain high in the area of focus. You can get some creative shots by getting very close to your subject (13cm is just 3.5cm beyond the lens hood). I could mostly fill the frame with a pair of Airpods in case.

It is an interesting way to add some storytelling to your images and I appreciate the additional creative options that it provides. I found the background blur more pleasing from the 14mm than the 9mm despite the APS-C lens having the larger maximum aperture. We’ll delve into that a bit more in the image quality section.

Viltrox’s more expensive lens series have weathersealing, but the budget AIR series does not. The AIR 9mm does have a HD Nano multilayer coating with water-resistant and antifouling coating on the front element.

Though the AIR series is short on bells and whistles, the Viltrox AF 9mm F2.8 AIR, like other lenses in the series, feels sturdy and well made. It is lightweight, will balance easily on a wide variety of camera bodies and sizes, and doesn’t really feel “cheap” in any way.

Autofocus

The Viltrox AF 9mm F2.8 AIR, like other AIR lenses, utilizes a lead-screw type stepping focus motor (STM) that makes for fast and quiet focus changes. Focus felt silent unless I put my ear up next to the barrel, and even then I could hear very little focus noise other than a slight click from the aperture blades at first. The combination of a wide focal length and a small maximum aperture means that focus changes are minimal, and the result is that autofocus basically feels instant all the time.

Focus was reactive enough to successfully grab bees in flight as they arrived back at the hive, and you can see from the foreground and background that focus is intentionally in the right place.

Here’s another shot that shows good accuracy.

That means that slower, easier subjects were no problem. A sleeping cat was no match for this focus system.

Expect the AIR 9mm to have a slightly easier time focusing in low light situations than the full frame 14mm F4. F2.8 lets in twice as much light as F4, meaning that the 9mm will give the camera’s focus system more light to work with.

In most situations focus will be so fast that you don’t even think about it. No problem there.

Video AF

Video AF is also good in the ways that matter. The amount of focus change is minimal, allowing focus pulls to be very subtle. There is a bit of focus breathing, but it isn’t pronounced. Focus moved smoothly back and forth between the subjects in my test with no pulsing or settling.

My hand test (where I alternately block the camera’s view of my face with my hand and then remove it) went fine, though the focus changes are so subtle that you scarcely notice if focus is moving from my hand to my eye and back.

Perhaps more important for this lens was my vlogging test, where focus had no problem staying locked on my face as I moved around walking with the camera. This should be a really great option for vlogging due to having a great focal length, light weight, and stable autofocus. It should work equally well for gimbal work for similar reasons.

Image Quality

The Viltrox AF 0mm F2.8 AIR has an optical design of 13 elements in 11 groups, making it a bit more complex than the 14mm F4 (probably mostly due to that larger maximum aperture). A whopping eight of these are exotic elements, including three ED (extra-low dispersion) elements, 3 HR (high refractive index) elements, and 2 ASPH (aspherical) lenses. The MTF has a very similar signature to the 14mm F4, though just a little bit better over much of range. Like the 14mm F4, the lens is actually a little sharper at F2.8 than it is stopped down to F8 everywhere save the extreme corners. The MTF shows an extremely sharp center and a fairly steady but mild slide to the corners. Astigmatism is low (the sagittal and meridional planes stay closely aligned), suggesting strong contrast even in to the corners.

Real world results certainly affirm that, as the lens delivers surprisingly strong, high contrast results all across the frame.

This definitely feels like a lens that could not only easily handle the 26MP sensor that I’m testing it on here on Sony, but also the 40MP sensor on Fuji as well. This could be a good budget alternative to the much more expensive Fujinon XF 8mm F3.5 WR that I reviewed here.

We’ll work through the chart results by first looking at distortion and vignette.

The upside on the distortion front is that the overall quantity of distortion is very low for a 9mm lens. I had to use a massive +25 to correct the barrel distortion on the Fuji 8mm, but the AIR 14mm only required correction in the +8 range. That’s the good news.

The bad news is that the correction is fairly complex, and the process of correcting some barrel distortion in the heart of the image creates some pincushion distortion near the edges. Fortunately the correction profile (which should be available by the retail release of the lens) will undoubtedly correct the distortion in a more linear fashion.

Even uncorrected, however, the low amount of the distortion meant that I could shoot without concern of seeing distortion on most subjects. This interior shot shows clean lines and low distortion, making this a very appealing budget real estate lens (there is not corrections applied to this shot – it is straight-out-of-camera.

Vignette is moderate, requiring right over +50 to correct, which is about +25 less than I had to use on the Fuji (which also has a slower aperture of F3.5). Here’s another interior shot with no correction, showing that images right out of camera are perfectly usable in most situations.

Bottom line is that the wide angle of view and low native distortion make the Viltrox stand out from most competing lenses. It is relying much less on software corrections that most of the lenses I see in this class.

Viltrox seems to have discovered the formula for largely eliminating fringing in their lenses. The 9mm F2.8 shows almost no longitudinal chromatic aberrations. Fringing is pretty much perfectly corrected.

Lateral Chromatic Aberrations usually show up along the edges of the frame as fringing on either side of high contrast areas (like bare branches framed at the edge of images). there is a very mild amount of fringing on the highest contrast areas, but hardly enough to notice in real world use.

So how about resolution and contrast? All chart tests done with APS-C mode of the Sony a7RV (26MP) using a tripod and a two second timer. Here’s a look at my test chart:

And here are the crops (at roughly 200% magnification) from the center, mid-frame, and extreme corner at F2.8:

The results are really excellent. The center is fantastically sharp, but the midframe also stands out as being exceptionally good. The corners show some fade out near the edge, but are very good relative to many wide angle lenses.

You can get very good results even at F2.8 with great contrast, detail, and color.

While the corners aren’t as sharp as the center at F2.8, they are still perfectly usable even at landscape distances.

The copy I tested showed excellent centering, with consistent performance in all four corners.

Stopping down to F4 doesn’t change things much across the most of the frame, though you will see a bit of improvement in the corners.

Sharpness consistency seems to peak at F5.6, with a mild regression by F8.

Real world shots in this aperture range look great all across the frame.

Diffraction will show up as per usual, with some visible softening by F11 that becomes more pronounced by the minimum aperture of F16.

Viltrox has continued to improve their optical glass, and the result is that colors are rich and accurate.

You shouldn’t buy a lens like this for the purpose of strongly blurring backgrounds, but the close focus capabilities of the 9mm AIR do allow you to get close and blur out backgrounds. In many cases I find the bokeh quality to be a little busy for my tastes, with more outlining than what I would prefer.

Here’s another shows, in particular, some outlining around specular highlights.

The best case scenario is when the subject is close and the background a little further away.

Bokeh is subjective, so if you like what you see, all the better.

Flare resistance is fairly good, with good contrast, though there will be a bit of ghosting, particularly at smaller apertures. Here’s a variety of images and compositions to demonstrate.

There is mostly good news on the coma front, as I found that generally nightscape images looked good. Star points are nice and crisp, the angle of view is very wide, and vignette isn’t too bad. There’s a bit of coma in the extreme corners, but it is pretty minimal.

I would call this one of the best budget astro lenses that I’ve seen. It checks a lot of the boxes for very little money.

Put simply, this is another very impressive lens from Viltrox. It is going to be hard for other lens makers to compete with this kind of quality at this little of a price tag. Here’s a mini-gallery of other images for you to enjoy.

Conclusion

The pairing of the 9mm F2.8 and 14mm F4 lenses to simultaneously serve the APS-C and full frame markets with similar lenses is a really unique approach by Viltrox, and frankly, it makes a lot of sense. While both lenses do have unique character, you can definitely see a lot of commonalities. It seems logical to leverage the engineering required to design a wide angle lens like this and to make lenses for both sensor sizes, and both lenses are in my mind triumphs because they combine very wide angles of views, compact size and weight, and excellent performance in extremely affordable packages.

We have gotten far too accustomed to lens makers lazily using software corrections to make wide angle lenses “work”, but Viltrox just showed that it doesn’t have to be that way. The Viltrox AF 9mm F2.8 AIR is compact and yet has low levels of distortion and reasonable levels of vignette despite the focal length/aperture combination.

This is going to make a top notch wide angle prime for a lot of unique purposes, from vlogging or gimbal work on the video side of things to real estate, architecture, landscapes, street, and astrophotography on the stills side of the camera. It does everything competently, and that makes the Viltrox AIR 9mm F2.8 an easy lens to recommend…particularly when you can get it for for about $190 USD after the discount!

Pros:

Widest lens for Viltrox ever
Lightweight, compact design
Lens feels tough and well made
Well executed, smooth manual focus ring
Includes lens hood and pouch
USB-C port for firmware updates
Excellent focus accuracy
Good focus speed
Strong video focus
Low focus breathing
Exceptional sharpness from F2.8 on
High maximum magnification
Great contrast
Low distortion
Moderate vignette for so compact a lens
Good color rendering
Good flare resistance
Fantastic price to performance ratio

Cons:

No weather sealing or features
Distortion a bit complex
Bokeh is a little busy

__________________________________________________________________________________________________

GEAR USED:

___________________________________________________________________________________________________________

___________________________________________________________________

___________________________________________________________________

Want to support this channel? Use these affiliate links to shop at: B&H Photo | Amazon | Adorama | Camera Canada | Amazon Canada | Amazon UK | Ebay | Make a donation via Paypal

Buy DA Merchandise https://bit.ly/TWIMerch

Keywords: Viltrox, Viltrox AIR 9mm F2.8, Viltrox AF 9mm F2.8 AIR, AIR, Viltrox AF, Viltrox 14mm, Viltrox 9mm F2.8, f/2.8, 9mm STM, AF, a6700, Sony ZV-1, Fujifilm X-T5, X-H2, X-E5, Review, Review, Hands On, Dustin Abbott, Real World, Comparison, Sharpness, Bokeh, Flare Resistance, Autofocus, Image Quality, Sample Images, Video, Portrait, #viltrox, #letthelightin, #viltroxAF289, #DA, #viltrox9air, #carrylesscapturemore, #viltrox9AF, #viltroxAIR2809