The Irix 15mm f/2.4 Blackstone is the premium build variant of the fast ultra-wide prime, distinguished from the lighter Firefly version by heavier, more robust aluminium and magnesium construction. The optical formula is identical — the Blackstone adds premium build quality and weather sealing.
The f/2.4 at 15mm provides exceptional capability for astrophotography and low-light wide-angle work with the same rectilinear design as the Firefly. The Blackstone's metal construction adds weather resistance and a more substantial, professional feel compared to the lighter alternative.
Build quality is the premium Blackstone tier with magnesium alloy and aluminium construction providing weather resistance and robust handling. The infinity click and rear gel filter slot are shared with the Firefly, but the Blackstone adds genuine weather protection.
The Irix 15mm f/2.4 Blackstone offers the premium build variant at moderate premium over the Firefly. The weather resistance and robust construction suit demanding outdoor and astrophotography conditions where equipment durability matters.