Firefly – the lightweight Irix series for field work

TheFireflyline focuses on low weight, comfortable handling and travel practicality. Its ergonomic focus ring has a rubberized grip for confident manual focusing.

Firefly usesthree rubber sealsto help protect the camera mount and focusing mechanism from dust, moisture and accidental splashes.

Firefly or Blackstone – what is the difference?

Firefly and Blackstone share the Irix 11mm f/4 concept but target different priorities.Fireflyis lighter, uses a rubberized focus ring and is especially travel-friendly.Blackstoneemphasizes premium finishing, an aluminium-magnesium alloy body and engraved fluorescent markings.

Landscape, architecture and interiors

An 11 mm focal length can capture expansive landscapes, large buildings and tight interiors where stepping farther back is impossible. The extreme perspective is also useful for compositions with a strongly emphasized foreground.

Rectilinear 126° – ultra-wide without the typical fisheye look

The lens uses arectilineardesign, aiming to keep straight lines more natural despite the huge126° angle of view. The manufacturer specifies distortion of about3.13%a useful characteristic for architecture and interiors.

Special optical elements and Neutrino Coating

The optical system uses four high-refractive HR elements, two ED elements and three aspherical elements.Neutrino Coatinghelps reduce aberrations, reflections and flare while maintaining good contrast and colour consistency.

Focus Lock and Infinity Click

Focus Locklets you secure the chosen focus position, which is especially useful for tripod work, panoramas and astrophotography.Infinity Clickhelps you feel the infinity position without constantly checking the scale.

0.28 m close focusing and 9 aperture blades

The minimum focusing distance is0.28 mallowing dramatic foreground emphasis. The diaphragm uses9 rounded bladesfor smoother rendering of out-of-focus areas.

30 × 30 mm gelatin filters

Because of the protruding front element, conventional front screw-in filters are not used. A rear holder accepts30 × 30 mm gelatin filterskeeping filteration possible with such an extreme ultra-wide design.

Pentax K – the correct mount for Pentax DSLRs

This version uses thePentax K mountand fits compatible Pentax K-mount DSLRs directly, including full-frame and APS-C bodies.

Adapting the Pentax K version to other mirrorless systems requires a suitable adapter; the electronic functions retained then depend on the adapter and camera body.

The lens focuses manually but has a built-in electronic module.On a compatible body it enables camera-controlled aperture, PASM modes, EXIF recording and focus confirmation.

Key specifications

• series:Firefly
• model:Irix 11mm f/4 Firefly
• version:Pentax K
• focal length:11 mm
• maximum aperture:f/4
• type:ultra-wide, rectilinear
• focusing:manual
• angle of view:126°
• minimum focusing distance:0.28 m
• aperture blades:9, rounded
• special optical elements:4 HR, 2 ED, 3 aspherical
• Focus Lock:yes
• Infinity Click:yes
• filters:rear 30 × 30 mm gelatin filters
• sensor format:full frame and APS-C.
• aperture control:electronically from the camera body
• communication:PASM modes, EXIF recording and focus confirmation.

What is included

• Irix 11mm f/4 Firefly lens for Pentax K
• lens hood
• front lens cap
• 2 rear lens caps
• soft pouch
• original packaging.