Irix 15mm f/2.4 Blackstone (Pentax)

Irix 15mm f/2.4 Blackstone (Pentax)

Designed in Switzerland and manufactured in Korea, Irix lenses are available in two different versions; the Blackstone with a magnesium-aluminum alloy body and the Firefly with a plastic body. The advantage of the plastic body is that it weighs up to 12%. The manufacturer claims that the Firefly series lenses are the lightest in their class.

Other differences between Firefly and Blackstone versions

• The Blackstone body is coated with a scratch-resistant coating
• Blackstone metal focusing ring for grooves
• Firefly focus ring rubber coated
• Blackstone frame markings engraved and painted with fluorescent and UV-protected paint. Markings are visible even in low light
• Firefly frame markings printed on the frame
• Blackstone comes with a hard protective bag for the lens
• Firefly comes with a soft fabric protective bag for the lens
• Both are weatherproof. In the Blackstone version, weatherproofing is also found behind the front element.
  

• Suitable for full-frame camera bodies
• Manual focus
• Aperture can be adjusted from the camera
• Focus lock. You can lock the focus at any point
• Weatherproof
• 95mm filter thread and slot for gelatin filter

The Irix 15 mm f/2.4 is a fast, weather-sealed, ultra-wide-angle lens for full-frame cameras. The focal length is excellent for indoor and landscape photography, and its brightness is also excellent for starry skies and northern lights photography.

The manufacturer has made it easier to focus Irix lenses to infinity. There is a stopper at infinity that keeps the clicking sound when the focus ring is turned to infinity. This is a great feature when, for example, you are shooting in the dark and need to focus at infinity. However, many things affect the infinity position, such as temperature. The infinity adjusted after the factory is not necessarily exactly right. However, the lens can help with this. You can adjust the focus scale yourself, as the lens has a removable cover and an adjustment screw under it.

In addition to focusing, the lens also features focus lock. A feature that allows you to lock the focus at any point without worrying about accidentally turning the focus ring and causing the focus to shift. Once the focus is locked, the focus will not change either way.

Unlike other wide-angle lenses, it is possible to attach a filter to the Irix lens. Either on the nose of the lens, where there is a 95mm filter thread, or on the back of the lens, where there is a place for a gelatin filter.

Specifications:

• Focal length: 15 mm
• Viewing angle: 110? (diagonal)
• Focusing distance: 0.28 m (0.92 ft) - ?
• Focus: manual, focus lock
• Aperture: f/2.4 – f/22
• Aperture Shape 9 rounded blades
• Construction: 15 elements / 11 groups (3x HR, 2x ED, 2x ASP)
• Filter thread: 95mm
• Gelatin filter: 30 x 30 mm
• Dimensions: 114 x 100 mm
• Weight: 685g