Irix 15mm F2.4 Firefly & Blackstone Review

Conclusion

Irix made a splash when they launched the 15mm F2.4. With its wide angle, fast aperture, claims of high optical performances and, most importantly, support for Pentax's K-mount, it drew the attention of many.

Offered in two versions, the Irix 15mm has a lot going for it. The more affordable Firefly features a plastic body, lower weight, partial weather sealing. Optically, it is identical to its more expensive sibling, the Blackstone which offers full WR, a metal body and fluorescent, engraved lettering.

Even though the lenses are manual focus, they do offer fully automated aperture control and, in fact, lack an aperture ring. The lens is large, well made and superbly assembled, especially the Blackstone version. The amount of information displayed on the focus ring is impressive, and well in line with the lens' intended use. 

The wide field of view takes some time getting used to, especially on full frame. Making a rectilinear lens at this focal length inevitably comes with a few compromises. In the present case, it comes in the shape of strong vignetting at all apertures, flare which is, again, visible at all apertures and high distortion. The latter is to be expected, to some extent, on an ultra wide lens. Sadly, being a third-party lens, the Irix 15mm cannot benefit from in-camera correction.

Our test subjects were also plagued with some decentering, an occurrence which appears to be relatively common for this lens. The manufacturer appears to offer good after-sale support and to correct decentering when it occurs, at least.

All is not dark, luckily. The lens certainly delivers on sharpness, with good to excellent figures at medium apertures, and an impressive uniformity across the frame. The corners are never as good as the center (which is to be expected) but they are close enough to serve as a landscape lens. Smaller apertures are usable but sharpness decreases starting at F11.

Chromatic aberration is, quite simply, a non-issue. This is nothing short of stunning, and commendable.

Pros

  • Excellent build quality, in particular for the Blackstone version
  • Lots of information, adjustments and controls on barrel, make usage easier
  • Pleasing bokeh, especially highlights
  • Good sharpness at medium apertures
  • No trace of chromatic aberration
  • Good manual focus
  • Capable of creating beautiful images with rich colors

Cons

  • Dramatic vignetting on full frame
  • Flare present and obvious at all times
  • Soft corners at wider apertures, general softness at smaller apertures
  • Important distortion
  • Decentering issues

Pricing

The Irix 15mm F2.4 comes in two versions, the premium Blackstone commanding a street price of $574.95 while the least expensive Firefly costing $475 in March 2018.

Rating

What the Firefly version boasts in terms of value, the Blackstone makes up with its premium build and full weather sealing.  At the end of the day, we give both lenses the same score.  Hats off to Irix for giving users the flexibility to go down their preferred route.

Build Quality 
 9
Sharpness 
 8
Bokeh 
 8
Aberrations 
 6
Distortions 
 7
Handling 
 8
Value 
 8
Overall 
 7.7 (Good)

Who is it For

The Irix 15mm F2.4 is a relatively inexpensive lens for what it is. Considering its build quality, acceptable optical performance and fast aperture, it is a good candidate for users interested in ultra wide angle on full frame without breaking the bank. Well suited for landscapes and cityscapes, it is a rugged product which should serve for many years.

The Bottom Line

As a newcomer in the photography market, Irix succeeded in creating a lens worthy of interest. While it is not without flaws, the 15mm F2.4 has a lot going for it.  It's in a particularly strong spot given the fact that it has no direct competitors from the genuine Pentax line, which currently lacks ultra-wide primes for full-frame.

Be sure to check the user reviews for the Firefly and Blackstone or post your own if you already own this lens.

Comments

 

 


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