Irix 15mm f/2.8 Blackstone Ultra-Wide Angle Prime Lens for Pentax K

Architectural photographers capturing sweeping interiors, landscape shooters chasing dramatic skies, and astrophotographers hunting the Milky Way all reach for the Irix 15mm f/2.8 Blackstone. Its 110° angle of view on full-frame sensors pulls entire scenes into frame with minimal distortion, while the bright f/2.8 aperture keeps handheld shooting viable in low light. Built around a magnesium-aluminum alloy barrel with four internal seals, this manual focus prime shrugs off dust, moisture, and rough handling on location.

Key specifications

• Ultra-wide 15mm focal length for full-frame and APS-C Pentax K-mount cameras
• Fast f/2.8 maximum aperture, stopping down to f/22
• Advanced optical design: 15 elements in 11 groups, including 3 high-refractive, 2 extra-low dispersion, and 2 aspherical elements
• Rounded 9-blade diaphragm for smooth bokeh and pleasing sunstars
• Close focusing to 0.28 m with 1:7.7 maximum magnification
• 95mm front filter thread plus rear gel filter slot (30x30mm)
• Weather-sealed construction with 4 internal seals
• Focus lock, hyperfocal scale, infinity click, and UV-reactive engravings

Why choose it

The Blackstone edition pairs premium optics with a rugged, all-metal body that feels solid in hand. Manual focus with a long, precise throw gives you complete control for critical sharpness, while the hyperfocal scale and focus lock make zone focusing fast and repeatable. The rear gel filter slot is a bonus for ND or color correction without bulky front filters.

Ideal use cases

• Architectural and real estate photography
• Landscape and nature photography
• Astrophotography and night sky imaging
• Interior and environmental portraiture
• Creative wide-angle videography

Good to know

The Irix 15mm f/2.8 Blackstone is a fully manual lens with no electronic contacts, so aperture control is via the lens ring and focus is manual only. It is compatible with Pentax K-mount DSLRs and can be used on APS-C bodies with an equivalent focal length of approximately 22.5mm. The lens features a detachable hood and a front cap, and the rear gel filter slot accepts standard 30x30mm gel filters for fine-tuning color or exposure without adding front filter bulk.