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While I haven’t done many lens reviews up to this point, I’ve owned many (too many) X-mount lenses sine I jumped into the world of Fujifilm cameras a couple years ago. The Viltrox Air series has made some great additions to the Fuji third party options on the market, and their new 15mm f/1.7 just that.

I want to point out that I am not a professional photographer and my lens reviews won’t be hyper-technical. I might do just a little pixel-peeping but there won’t be test charts or anything like that in this review. I also want to point out that Viltrox did not send me the 15mm f/1.7 X-mount lens, I purchased it myself. I do, however, have an affiliate account with Viltrox and if you click on my links and make a purchase I receive a small commission, which helps to support maintenance of this site.

Physical Specs & Handling

Physically, the 15mm f/1.7 is very similar to its “air” series siblings from Viltrox though the specs amongst them are not identical. At 180g it’s quite light, but certainly not unheard of in the X-Mount world. This size and weight stands out a bit more (in a good way) in the world of, say, Sony E-Mount lenses, where the average APS-C lens can top 400g such as the Sigma 16mm f/1.4 (405g). Nonetheless, the X-Mount air series lenses don’t feel out of place on my X-E5 or X-T5.

For the price, the build quality feels to me like it has compromises in the right places. The body is the same plastic as the rest of the air series which feels fine at this price but certainly not as rugged as Fuji’s metal lenses. The lens mount is metal and there is a USB-C port in the mount for firmware updates. There is no weather sealing.

General Use & Performance

Generally speaking, the Viltrox 15mm f/1.7 was pleasant to use in multiple scenarios. Going for a walk, I was able to use it for fairly close subjects wide open and get decent background separation. I did, however get mixed results when it comes to backlight scenes and chromatic aberration. The sample photos below taken with my X-E5 in the HEIF format (converted to JPEG for uploading) have had mild Lightroom processing applied to tame highlights and lift shadows, but no correction for aberration or other flaws and they did not have a film recipe applied in-camera (no effects).

Take a look at the image looking up at tree branches with the sun poking through. That’s a challenging image for any lens, but surprisingly there isn’t a lot distracting color fringing – it’s there, but not stealing attention. Conversely, check out the other two images of the tree trunk. The bright blue fringing around the branches that are set against a bright sky in the background is screaming “look at me!”. Ultimately the aberration performance is not bad, but also not terrific by 2025 standards for a new lens.

I should note that I did not use the included hood (which is pretty shallow), but outside of those situations with strong backlighting, I didn’t come across major issues with flaring or other light-based flaws.

Autofocus was quiet, snappy and relatively confident during my testing with an X-T5 and X-E5, though I’m not sure how it will fare on Fuji’s older bodies. I only had a little uncertainty in AF-S mode in scenarios with very low light or intense backlighting, but the experience in those scenarios is only slightly better with Fuji’s best-focusing LM lenses like the 23mm f/1.4.

Compared to Fuji 16mm f/2.8

The Fuji 16mm f/2.8 R WR (MSRP $449 US) is a lens that I never personally loved, but kept it with me on trips because of its very small size and wider angle in case I wanted to grab some architecture or wide landscape photos. I don’t love it because it’s a little soft at f/2.8 and in lower-light scenarios like, for example, shooting the interior of a historic building or museum, the f/2.8 max aperture requires bumping up the ISO more than I’d like. What I do like about the lens is how tiny it is. It has looked very at-home on my travel cameras including my previous X-E4, X-T50, and my current X-E5.

The Fuji 16mm f/2.8 might have a size/weight (155g vs 180g) and weather-resistance advantage over the Viltrox 15mm f/1.7, but for me that’s pretty much where it ends. It does also have less vignette but I personally will trade that for a brighter aperture. Starting with sharpness, let’s look at the most clinical comparison I’m going to do – the “brick wall” sharpness test.

At f/1.7, the Viltrox is about as sharp as the Fuji is at f/2.8, which means the Viltrox is usable wide-open. Stopped down to f/2.8, the Viltrox is sharper, especially in the corners. There is noticeably more vignette on the Viltrox, however.

Once we get down to f/4.0 they are looking more similar with a slight edge for the Viltrox – still more noticeable in the corners, and f/5.6 is where they start to look the same unless you are doing some crazy pixel-peeping. The Viltrox’s strong vignette never totally goes away though, even at landscape apertures. It does, however, brighten up fairly easily in post if it bothers you.

Here is one more comparison taken with the Classic Chrome film simulation and mild processing in Lightroom to turn the highlights down a touch. The vignette on the viltrox is still quite noticeable in the corners of the sky, even at f/5.6.

Final Thoughts

I can sum up my thoughts about the Viltrox 15mm f/1.7 by saying that when I need a wide angle and compact size, I’ll most likely be bringing this lens instead of the Fuji 16mm f/2.8. I prefer it for the sharpness and brighter aperture which makes it more useful on days when I transition from outdoors to indoors multiple times (ex: on vacation). I personally will only take the 16mm f/2.8 in its place if size or weather sealing are the top priority of the day.

If you don’t own a wide angle prime for X-Mount and are considering your options, the Viltrox 15mm f/1.7 should be on your list.