Review: IRIX 15mm F2.4 FireFly (Canon EF, Used on Sony FE)

fall landscape photography

The IRIX 15mm f2.4 FireFly has lots of the benefits of its bigger brother with very few drawbacks.

Earlier on, we reviewed the IRIX 15mm f2.4 BlackStone, which is considered to be the higher end option to the IRIX 15mm f2.4 FireFly. That lens was great, and in our findings we recently found the IRIX 15mm f2.4 FireFly to be pretty much just as great. Both lenses have weather sealing, both are manual focus, both can lock their focus and they have innovative features compared to many other options on the market. Of course, they both have fantastic optics. The major advantage of the Blackstone? A metal body, slightly better image quality (though noticeable), and a special, black light-illuminated material in the ink on the lens. But if you don’t care for any of that, the IRIX 15mm f2.4 FireFly survived with us through rainstorms.

Pros and Cons


  • Weather sealing
  • Fairly lightweight
  • Accurate focusing depth of field markers
  • Sharp optics
  • Innovative features like the ability to lock the focus with a separate ring


  • Focusing communication with a Sony FE camera via a Metabones adapter wasn’t the absolute best.

Gear Used

We tested the IRIX 15mm f2.4 FireFly with the Sony a7r III, Canon 6D Mk II, and the Metabones EF to FE adapter.

IRIX 15mm f2.4 FireFly Tech Specs


The IRIX 15mm f2.4 FireFly is a fairly complex, manual-focusing optic in terms of how it looks. There is a front filter thread of 92mm (that’s huge). And it gets even more complicated.

On the body you see two main controls. The one closer to the front of the lens is the lock. This allows the photographer to lock the focusing. Behind that is a textured rubber ring for focusing.

The lens has depth of field and distance scales on it. In addition to that, the focusing ring has a tab on it to make focusing a bit easier.

Build Quality

The IRIX 15mm f2.4 FireFly has weather sealing incorporated into the lens everywhere but the front of the lens. So if you’re shooting, be sure to keep the front covered or get a filter for it. Granted, it’s a massive front filter. Despite the lack of weather sealing and the plastic body, it’s still designed and built very well; nothing about it feels cheap. In hands of varying sizes, the IRIX 15mm f2.4 FireFly will feel comfortable due to not only its chunky design but also because of the rubber grip.

Ease of Use

The IRIX 15mm f2.4 FireFly is a manual focus lens. Right off the bat, if you hate manual focus you should slap yourself probably won’t like this lens. But it’s really easy to work with. You can always use focus peaking and magnification to figure out if you’re using it right. Also you should know that it has AF/EF contacts and so you can shoot with it in aperture priority and there will be lens data transmission through the lens to the camera.


Since the IRIX 15mm f2.4 FireFly is a manual focus lens you should know that there is a depth of field and zone focusing scale. It also has the ability to lock the focusing ring, tighten it, and at the infinity marker the lens will click to tell you that it’s focused all the way out. It’s pretty cool.

Image Quality

When using the IRIX 15mm f2.4 FireFly, we were very impressed with the image quality. For what it’s worth though, the image quality of the IRIX 15mm f2.4 FireFly was noticeably not as sharp as the IRIX 15mm f2.4 BlackStone. We found this a lot when we got out to the corners and when stopped down beyond f5.6.


The IRIX 15mm f2.4 FireFly can focus very closely and so to that end there is bound to be potential for bokeh. The bokeh isn’t creamy but it surely is hazy. It’s nice and if someone doesn’t know any better, they could think that this were medium format in quality.

Color Rendition

The IRIX 15mm f2.4 FireFly offers color rendition that is very nice and standard. It isn’t as saturated as Rokinon, Zeiss or Tamron for sure. Instead, it’s more akin to Tokina. I like the look.

Chromatic Aberration

We couldn’t find any major fringing issues, but we did find that the sharpness fell off a bit too soon for us.


The sharpest that this lens gets is at f5.6. Set it on a tripod and shoot with a high megapixel sensor. However, I still think that the coatings on the Blackstone lenses are apparent in their rendition of the sharpness.

Extra Image Samples



  • Build quality for the most part
  • Lightweight


  • I wish it were fully sealed
  • When you use this lens and the Blackstone, you want the Blackstone.

The IRIX 15mm f2.4 FireFly isn’t at all a bad lens. But it isn’t as good as its Blackstone variant. It isn’t as sharp or as well built. But that doesn’t mean that it isn’t still well built or sharp. It surely is both of these things and at the budget entry, it’s difficult to get a weather sealed lens like this. For only $375, you’re getting a damned great deal.

The IRIX 15mm f2.4 FireFly receives four out of five stars.

Recommended Cameras

  • Canon 5DS: Canon’s highest megapixel DSLR deserves a lens like this.
  • Nikon D850: There’s no good reason not to use this lens on the weather sealed D850
  • Sony a7r III: With an adapter, the Sony a7r III is a great option.

Chris Gampat

Chris Gampat is the Editor in Chief, Founder, and Publisher of the Phoblographer. He also likes pizza.