Crisp, Fast, and Wide: Fstoppers Reviews the Irix 15mm f/2.4 Wide-Angle Lens

Meet the Irix 15mm f/2.4 Blackstone, a wide-angle lens designed for photographers who need a dependable lens even in extreme situations. The lens, coming to you from TH Swiss Company, first debuted in 2016 and is now widely available for Canon, Nikon, and Pentax mount systems.

Irix does make two different versions of this lens: the Firefly which is the standard version of the lens, and the Blackstone which is the premium version of the lens. For the purposes of this review, I worked solely with the Blackstone version. Seeing that their first lens was released just in 2016, Irix is pretty new to the game, but they started out on the right track in developing a lens that could endure a beating and offer some fantastic creative control for photographers seeking a wide-angle composition.

Build Quality

With a durable body made of aluminum and magnesium, this lens looks and feels like it can take a beating (not that you'd really want to do that). The lens elements are clearly machined with precision; everything fits nice and snug together and move smoothly when adjusting focus on the lens. The lens is weather sealed, in addition to the durable body, by four interior rubber seals that protect both the camera mount and focusing mechanism against dust and moisture (water resistant, not waterproof). The lens is built for the use of both 95mm screw-in filters on the front of the lens and also gelatin filters which slide in a small slot at the back of the lens. For the Blackstone, the premium version, the engraved lens markings are fluorescent which makes it that much easier to operate and make adjustments in low light situations.

Focusing

Although the lens was designed for electronic control of the aperture settings, focusing for this one is all manual. Focusing is very smooth. The focus ring has a very crisp and smooth feel to it whenever you adjust focus. The distance between the minimum focal range of 0.28 meters (0.92 feet) and infinite focus is quite large along the ring, making it much easier to set and refine your focus.

One of my favorite features of this lens is what Irix calls the "infinity click." When you adjust the focus ring to set the lens on the "infinity" position, there is a noticeable click when the ring hits that position. This makes it very easy to find or reset your infinity focus even when you have difficulty seeing the markings on the outside of the lens or even looking through the viewfinder. The addition of the focus lock ring is particularly helpful when you need to set focus once and not have to worry about bumping your camera which might adjust your focus on other lenses. I found this to be helpful when shooting in Zion National Park, particularly when I was hiking up the Narrows. I was able to set my gear once, take a shot, and then hike to my next shoot spot without having to worry about whether the lens was still in focus or not.

Flare and Ghosting

The special neutrino coating is one that Irix developed to help attain better contrast while keeping color aberration, ghosting, and flaring to a minimum. From what I've shot with this lens so far, what I have noticed as far as flaring and ghosting seems to be consistent with other reputable, high-quality lenses. I still got flare and ghosts in some of my shots, but they were still very clean and in many cases as good as one could hope for. With nine aperture blades your sunstars will have 18 points, which for me is a plus as I like how that looks. Obviously any flaring or ghosting will be dependent on your shoot conditions and the composition itself. The image below is one that had the most noticeable elements, which is why it is included in this review. As you can see, as far as flaring and ghosts go, it's still pretty clean.

Aberrations and Distortion

Realistically, this is one of the best lenses I've ever worked with as far as handling such a wide angle without having to deal with much dramatic distortion or aberration. For such a wide lens, I was legitimately impressed with how each image came out. Sure, there is a little bit of in-camera distortion and vignetting, but not nearly as much as what I expected to see. Irix has also made their own lens profiles available for download for post-processing lens corrections. But even without the profile corrections, I was still very happy with how each image turned out. Below is an example of the shot before lens profile corrections and after the corrections have been applied.

As far as aberration goes, this is probably one of the best lenses with which I have ever worked. Below is the best example I could find out of all the shots I took with it that showed any chromatic aberration and, even then, it barely shows any at all. I've taken a range of images of different subjects at different times of day, and still this is one of the only images that showed even a little bit of chromatic aberration. I am legitimately impressed with how the Irix holds up here.

Image Quality

Let's be honest, this is usually what makes or breaks it for a lens. I've taken this lens into several various situations both during the day and at night and I am pretty solidly happy with the results I've been able to get from using it.

Sharpness

This lens actually holds its own very well with image sharpness. I have been incredibly happy with the sharpness across the entire frame. Below is an example of a square cropped image and a sample of the image zoomed in at 100 percent. You can see that edges retain great shape without too much issue. 

This image below is a sample taken at 100 percent of the top right corner of the image. You can see that we lose a bit of sharpness in the corners, but not a whole lot. 

Vignetting

The vignetting really isn't that bad, actually. To the point where I was still quite happy with the shots straight out of the camera, but when you apply their lens profile to correct the image, then the vignetting virtually disappears. 

Contrast

This is one area where this lens really does very, very well. Not only does it preserve the image with ideal levels for contrast, but the color translation is solid. It's not often where what you see is what you'll get, but this lens comes pretty damn close to delivering just that.

Overall, concerning image quality, I was quite impressed with how each image turned out. From maintaining image structure with very little distortion to color retention and sharpness, this lens really holds its own against other lenses in similar classes.

Low Light Handling

Granted, there are other prime lenses out there that have wider apertures at similar focal lengths. But I was very happy with what I was able to crank out with this lens opened up to f/2.5 while sticking to an ISO range of 1,600 to 6,400 for galaxy shots.

The wider aperture is great and as long as I didn't set up too close to my foreground then I didn't have to worry too much about focus stacking my shots even wide open. For low light work my favorite feature, by far, is the ability to lock the focus ring. I was able to set my focus for landscape work as soon as I got on location, lock it, and for the rest of the entire evening I didn't have to worry about resetting my focus even once. It was awesome; I could just move from shot, to shot, to shot.

Bokeh

I wasn't quite sure what to expect here. Most of my uses for wide-angle lenses don't involve getting very close to any of my subjects, so I almost forgot to go have some fun with close-ups at a wide open aperture. But I have to say, I am fairly impressed. The bokeh is smooth without any odd patterns or textures. Because the focus ring is so long in turn radius, it is pretty easy to compose your shot and then dial in your focus with precision. Especially since you have to be incredibly close to your subjects at 15mm in order to see much in the way of bokeh anyway.

Would I Buy It?

That's a great question. I think a purchase here will really depend on what your intended uses of the lens will be. Since you don't have the option for autofocus, it may be trickier for an events photographer, particularly if you're planning on shooting at wider apertures for such events. But if you're a landscape photographer, particularly if you shoot a lot of night skies or in low light conditions, then this would be a great lens for you. I'm telling you, the lock focus ring makes night shoots so incredibly smooth. 

What I Liked

• Great image quality across the range of aperture settings.
• Solid color and contrast retention.
• Large focus ring.
• Focus locking capability.
• Good, smooth bokeh.
• Solid control over coma.

What I Didn't Like

• Filter ring size being 95mm (compared to other lenses in a similar class) is one of the largest, making lens filters bigger, bulkier, and more expensive.

You can buy the Irix 15mm lens in both the Blackstone and Firefly versions now.