Viltrox 25mm F1.7 AIR Review (E-Mount)

Viltrox’s series of small, lightweight, and yet surprisingly high performing lenses is called the “Air” Series. We’ve seen 20mm F2.8 and 40mm F2.5 full frame lenses, the excellent 35mm F1.7 and 56mm F1.7 APS-C lens, and now we have a wider compliment to the two other APS-C lenses in the form of the Viltrox AIR 25mm F1.7 that I’m reviewing today. Viltrox has done enough in this series already that I’m really excited for each new release, and while I have liked the two full frame lenses, it is the now three APS-C lenses that have really shined. Their optical performance is much, much stronger than what their price tags suggest. It’s not very typical that a brand’s cheaper lineup of lenses (these F1.7 AIR lenses) exceeds the performance of their more expensive F1.4 lenses (23mm, 33mm, and 56mm F1.4 lenses), but that is absolutely the case here. The F1.4 lenses I’ve mentioned were reasonably good lenses, but they came during the era before Viltrox really gained confidence as a lensmaker (and, I believe, switched suppliers for their optical glass). I expected the new AIR 25mm to be a decent lens, and it hasn’t disappointed. It’s another very strong lens that can be had for a budget price of just $179 USD (or less, if you use the coupon code!). Is it worth checking out? 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 APS-C mode (26MP) of my Sony a7RV camera.

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Viltrox AIR Series Reviews:

Viltrox AF 20mm F2.8 (full frame)
Viltrox AF 40mm F2.5 (full frame)
Viltrox AF 25mm F1.7 (APS-C)
Viltrox AF 35mm F1.7 (APS-C)
Viltrox AF 56mm F1.7 (APS-C)

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Like the 35mm focal length, 25mm is a slightly oddball focal length on APS-C, landing at a 37.5mm full frame equivalent after you account for the 1.5x crop factor of Sony E (tested here), Fuji X, or Nikon Z APS-C cameras. It’s a little tighter than the standard 23mm focal length (34.5mm full frame), but not a tight as 27mm, which approximates the 40mm full frame focal length that is steadily growing in confidence. I’m wondering if Viltrox found the market somewhat confused by their having two 56mm lenses (the 56mm F1.7 was the first in this APS-C AIR series), and so they’ve chosen to release the 25mm and 35mm lenses with slightly different focal lengths from their previous 23mm and 33mm F1.4 lenses, which continue to be sold. The most obvious autofocusing 25mm alternative is the Zeiss Batis 25mm F2, a premium lens that has a slower maximum aperture but a huge price tag (MSRP is $1349). But that lens is a full frame (not APS-C lens, making it not really a direct competitor, either. Most other autofocusing 25mm lenses tend to be for Micro 4/3rds, which makes sense, as the 2x crop on that system makes those standard 50mm equivalent lenses.

To clear a bit of the confusion relative to the older F1.4 lenses: the AIR series of lenses have smaller maximum apertures (F1.7 rather than F1.4), have a slightly downgraded build (no aperture ring, plastic housing rather than metal), but are actually better lenses in terms of autofocus and optical performance. Viltrox has improved their optical glass, the smoothness and effectiveness of their autofocus motors, and has generally become much more competent in their optical designs. The AIR lenses are also smaller, lighter, and cheaper, which has led to them being quite popular.

Much like Samyang’s “Tiny series”, this lens is for those who don’t care about bells and whistles and just want a lightweight, high performing lens. This won’t be the series for those looking for aperture rings, buttons, or rings, but if you want a light, tough, high performing lens at a great price, prepare to be delighted with the new AIR 25mm.

Sound interesting? I suspect so, so let’s dive in a little deeper into the details.

Viltrox AIR 25mm F1.7 Build and Handling

The first thing to note is the slightly unusual maximum aperture value. Similar lenses are going to be F1.8, not F1.7, but I like this move as it sets the lens apart and gives it a small but real advantage over F1.8 lenses. F1.8 is 2/3rds of a stop slower than F1.4, while F1.7 is 1/2 half stop slower. That also means that this lens has a full half stop advantage over a lens like the Fuji 23mm F2. That’s a reasonably useful improvement, giving some additional light gathering and that slightly larger maximum aperture will also mean slightly larger and softer specular highlights, which helps close the gap a bit with F1.4 lenses. It’s worth noting that the Fuji lens also costs $450, which makes for a hard sell when you can get this one for $175.

As noted, the Viltrox AF 25mm F1.7 eschews the heavier metal casing typically used for the earlier Viltrox lenses and embraces a more conventional, lightweight design in polycarbonates (engineered plastics). I wouldn’t call the build high grade here, but what I can say is that nothing about the plastics feel flimsy. It doesn’t have the feel of the early Samyang Tiny series lenses but instead feels tough and durable; its the kind of lens that feels like it could survive some falls (not that I intentionally dropped it!)

The new AF 25mm F1.7 is extremely compact, only 64mm in diameter (2.6″) and 54.4mm in length (2.15″), making it pretty much identical in size to the 35mm and 56mm F1.7 lenses. It weighs only 170g (6oz), which is 1g less than the 56mm and identical to the 35mm. The 25mm and 35mm F1.7 look more like twins because of having the same lens hood design, but if you take that away, all three of these APS-C lenses look extremely similar.

That makes for a very compact profile on your camera. I don’t actually own a Sony APS-C camera (I use the excellent 26MP mode of my a7RV), but the Air 25mm is definitely light enough to be a great match even for a compact ZV-E10 II model.

Up front we have a 52mm filter thread, which is a small but relatively common filter size. The front of the lens fascia has a variety of information imprinted on it and has a classic profile. I’m a fan of having some lens information on the front fascia, as I feel it adds character to the lens.

There is an included lens hood that is essentially identical to the one included with the 35mm F1.7. It’s a little larger than the one included with the 56mm F1.7. It has high quality, thick plastics and feels like higher quality than the one with the 56mm. It also bayonets into place more precisely and stays locked into place better.

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.

This inexpensive series is set apart from most of Viltrox’s lenses in that there is no aperture ring in the design. There are no switches, either. 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, though I suspect it will be a little rougher on Fuji.

The Viltrox AF 25mm has 9 blades in its aperture iris. The blades do a very reasonable job of maintaining a circular shape as the aperture is stopped down. When stopped down far enough, an 18 bladed sunstar will emerge.

We have an important Viltrox standard in the form of a USB-C port on the metal lens mount that allows you to connect the lens to a computer and update the firmware directly. 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.

We’ve got a mild regression from the 35mm AIR when it comes to magnification. Whereas the AIR 25mm can focus a bit closer (30cm) than the 35mm (33cm), the much shorter focal length results in lower level of magnification at that focus distance. Maximum magnification is only 0.11x, which is definitely on the low side for a 35mm(ish) lens. Here’s what that looks like:

The previous Viltrox 23mm F1.4 could also focus as closely 30cm, but because of the shorter focal length it delivered a lower 0.10x magnification. You certainly won’t be able to do any “macro” work with the AIR 25mm, but you can certainly get close enough to blur out of a background.

Viltrox’ more expensive lens series have weathersealing, but the budget AIR series does not. The AIR 25mm 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 25mm F1.7, 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.

Viltrox AF 25mm F1.7 STM Autofocus for Stills

The Viltrox AF 25mm F1.7 STM, 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. Focus speed is well above average for a budget lens. In my focus tests I found that focus changes were fast and accurate, and even while doing the tests I felt a sense of surprise at how snappy focus felt.

I’ve got the benefit of reviewing the AIR 25mm on Sony, while I reviewed the AIR 35mm on Fuji, and there’s no question that autofocus is more sophisticated on the Sony side of things. That makes the AIR 25mm feel like the better focusing lens, though I suspect that if I had both lenses side by side on the same platform, I would find focus very similar. During the sequence of focus going back and forth during my tests, I snapped this shot on the fly, and it is perfectly focused.

General purpose shooting produced a lot of well focused results.

I tracked Nala walking towards me, and while I don’t think autofocus is GM-level in that situation, focus did keep up sufficient that images look properly focused.

For just getting street style shots where you need to pull focus quickly of people in motion, I saw zero issues. I took this shot (at F1.7) as a snap split second photo, and got a well focused end result.

I would categorize autofocus for stills as being rather excellent (at least on Sony). I have no hesitation in endorsing the behavior of this lens.

Focus for Video

Video AF was mostly very good. My focus pulls were smooth and without visible steps. Focus moved in a nicely linear fashion (no negative evidence of a stepping motor). What I didn’t like was an occasional micropulse on my foreground subject where focus did a little rack beyond proper focus and then settled back. Focusing breathing wasn’t non-existent, but it is quite low.

My hand test went pretty well, with successful transitions from my hand to my eye and back. The low focus breathing helped to keep the shot looking relatively cinematic. It’s worth noting that the footage also looked very sharp and with good subject delineation.

Real world shots that should be fairly static were just that. They locked on a subject and didn’t bounce around and pulse. I did shoot a shot of Nala, however, where I moved in towards her, and for whatever reason you can see some focus micro pulses taking place. The screenshot above shows that focus was actually good, and focus definitely didn’t need to make microadjustments all the time.

Overall I would say that focus is solid for both stills and video.

Viltrox AF 25mm F1.7 Image Quality

The Viltrox AF 25mm F1.7 has an optical design of 12 elements in ten groups, which is slightly more complex than the 35mm. Five of these are exotic elements, including one ED (extra-low dispersion) element, 2 HR (high refractive index) elements, and two aspherical element as a part of the design. The MTF looks excellent – sharper than the 35mm and slightly softer than the 56mm. There are very few lenses in this focus length range at any price that are giving this good of an optical performance (or better).

What’s interesting is that all of these APS-C AIR lenses are really producing image quality that is just about as good wide open as it is stopped down, with the F1.7 and the F8 MTF charts largely mirroring each other. This is actually a surprisingly sharp lens. It’s not hard to produce beautiful, highly detailed images with this lens, like this very cool (cold!) image of the Canadian Parliament library.

I shot at F2.8 to minimize any imperfections or smudges as I was shooting through glass and didn’t want the glass to be in focus. If I take a deep crop from that image, I can see good detail.

Before we jump into an evaluation of the optical performance, let’s take a quick look at the full frame coverage of the lens. I can’t do that when I’m testing the AIR lenses on Fuji, but since we are on Sony E-Mount for this one, it is an easy test. Here’s a full frame image:

So, it doesn’t cover the entire full frame image circle. You can see some “hard vignette” in the corners where light is completely blocked from the sensor. But what we can also see is that the AIR 25mm is covering the majority of the full frame image circle. In fact, if I do a bit of cropping, I come up with this:

You can see that the resulting full frame crop is still much wider than the APS-C image circle. The APS-C crop from the image is 26MP (6240 x 4160), but I can still get a usable 45MP (8288 x 5525) out of the full frame image. And frankly, there are some scenes where I can even get away with the hard vignette on the full frame image, like this:

A mild crop gives me this image:

That’s 48MP, which is great, and, what’s more, I think the AIR 25mm is actually doing a pretty good job of resolving that whole crop. Here’s a deep crop of the lower right corner of that image.

You could argue that the final 5% doesn’t look amazing, but I would say that it looks good enough. It does well enough in this situation that I could see taking this lens on a trip when I need to travel light and treating it basically like a 28mm full frame lens (after the crop) along with its more typical APS-C function.

Cool!

We’ll work through the chart results by first looking at distortion and vignette. The 25mm F1.7 does well in the distortion department but slips a bit with vignette.

I used a +4 to correct a small amount of barrel distortion. That’s not bad at all for a wide(ish) prime. Vignette required a +65 to correct (under 3 stops), though it is fairly linear and largely “works” for portraits, creating a natural vignette that draws the eye to the subject. I rarely found the need to correct the vignette in real world images, even though I was reviewing a prerelease copy before the time that any correction profile existed. This shot, for example, was shot at F1.7 and I saw no need for vignette correction.

Likewise this image from the National Art Gallery has received zero distortion correction, and yet the lines all look pretty good in a real world image.

Viltrox seems to have discovered the formula for largely eliminating fringing in their lenses. The 35mm F1.7 shows very low amounts of longitudinal chromatic aberrations. Fringing is well corrected, leaving very little fringing in my tests.

Real world results also look clean. You can see that contrast is good and there is only a minimum fringing in highly reflective surfaces and edges.

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 are minimal amounts of fringing on either side of the black/white transitions.

I also didn’t spot any issues in real world results, with branches in images looking clean of fringing.

So how about resolution and contrast? All chart tests done with the APS-C mode of my 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 F1.7:

We see here what the MTF chart suggested. There’s a very consistent performance across the frame, with the corners really not all that far behind the center performance. What’s more, while the recent TTArtisan AF 23mm F1.8 showed a really inconsistent centering result (at least in my copy), I actually found the centering in the Viltrox excellent, with all four corners performing at a similar level.

That leads to some impressively sharp wide open results, with a lot of detail and contrast even at F1.7.

This lens has no problem with Sony’s 26MP resolution, and I would say that it is strong enough to handle Fuji’s 40MP APS-C sensor as well, as I’ve found both the 35mm and 56mm AIR lenses to be solid on that platform.

Stopping down F2 does give a bit of contrast boost. It’s not huge, but I could see it all across the frame. I wanted to share the corners, as this is probably where I’m most impressed. I rarely see corners this good on such an inexpensive lens.

Stopping down to F2.8 shows another incremental improvement, though as the MTF suggests, a lot of the lens performance is available right from F1.7.

Landscape apertures look great, with great contrast and delineation of fine details. It was extremely cold during my primary review period, so I was out in a lot of weather at -20 or colder. You can almost watch the ice form on the river in real time at that temperature. This image shows great detail in the middle of the frame but also in all of the fine details in the bare trees in the upper left corner.

Diffraction isn’t quite as militant on a 26MP sensor as it is on the Fuji 40MP sensor, but you will still definitely see a softening effect at F11, and particularly at F16, though image quality never gets terrible.

This is a lens that repeatedly made me smile when I looked at images at 100% magnification. It’s actually pretty hard to believe that these sub-$200 lenses are so good.

I’ve been noting the improvement to Viltrox colors over the past two years since they switched suppliers for their optical glass. Once again I’m very happy with the color rendition from the lens, which feels neutral in color balance, nicely saturated, and with good contrast levels in the colors.

Even the deep Arctic cold days where it is cold, very bright, and colors can be a bit garish with lesser optical glass didn’t prove to be an issue here. I thought the colors in this shot looked exactly as they should considering the scene.

The challenge for lenses with good natural contrast (particularly those that aren’t huge to give the engineers space to try to do everything well) is that the bokeh quality suffers. A 25mm F1.7 APS-C lens isn’t going to crush backgrounds, but I actually found the bokeh pretty decent here. Specular highlights looked pretty good, with some lemon shape towards the edges but overall looking pretty decent.

If you want consistently round specular highlights, just stop down a bit. F2.5 makes for pretty good circular shapes across the frame.

This image shows a reasonably soft background without any jitteryness.

This shot looks good, too, with a typical room background looking fairly soft (and Nala looking very cute!)

I shot this chess set particularly for bokeh, and I would conclude that there is bit more outlining than I like, but frankly for a budget lens that also happens to be very sharp, that’s actually pretty great.

Changing the focus point gives you a bit of a look at foreground bokeh.

That looks okay, but what is actually very impressive is the microcontrast. I’m very impressed with how detailed the crop looks here.

Very crisp edges, low fringing, and a subject that really stands out even under high magnification. Impressive!

Flare resistance seemed better to me than what I saw with the 35mm. One of the earliest images I shared in the review showed a bit of a soft glow due to window lighting coming into the shot of Nala sleeping on a chair, but with direct sun coming through a window in the first shot of this series I saw no issues. I also saw very little ghosting or veiling in other very bright, direct sun images.

That’s 100% better than what I saw from the recent TTArtisan AF 23mm F1.8.

I also found that coma was fairly well controlled. The low fringing helps star points to look clean (no purple fringing), and there isn’t much comatic distortion near the edges of the frame.

Bottom line is that there really isn’t any particular areas of weakness for the Viltrox AIR 25mm, which is pretty insane in a $175 lens. If you want to see more images, visit the image gallery here.

Conclusion

I’m loving the Viltrox AIR series. These are lenses that are so easy to just grab and bring along because they are so compact and light, and yet the kind of image quality I’m getting doesn’t feel like I’m skimping on quality. The Viltrox AIR 23mm F1.7 gave me lots of images that I really enjoyed.

The AIR 25mm F1.7 has been a blast to use, with a great (though unique) focal length, great autofocus, and really great looking images.

The fact that all of these AIR lenses can be had for well under $200 each is an even bigger bonus, and so far I’ve been very impressed with the 25mm, 35mm, and 56mm lenses alike. This is a great walkaround lens, perfect for capturing the varied moments that life brings. It would be discrete enough for street, sharp enough for landscapes, and is just generally a lot of fun to use. I wouldn’t hesitate to buy this lens for my Sony, Fuji, or Nikon APS-C camera…particularly if you are using one of the small, light bodies and want lenses to match.

Pros:

Lightweight, compact design
Lens feels tough and well made
Well executed, smooth manual focus ring
Lens hood is improved
USB-C port for firmware updates
Good focus accuracy
Pretty good video focus
Outstanding sharpness from F1.7 on
Nice bokeh
Fairly low distortion
Good color rendering
Good flare resistance
Good coma performance
Fantastic price to performance ratio

Cons:

No weather sealing or features
Is 25mm a focal length APS-C shooters are looking for?

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GEAR USED:

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Purchase the Viltrox AF 56mm F1.7 @ Viltrox (use code DUSTINABBOTT for 8% off) | B&H Photo | Adorama | Nuzira | Amazon | Amazon Canada | Amazon UK | Amazon Germany

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