An impressively wide prime lens, the Pentax K-mount 15mm f/2.4 Firefly Lens from Irix meshes an advanced optical design with a lightweight, durable physical construction. The expansive field of view is complemented by a sophisticated optical layout that utilizes low dispersion, aspherical, and high-refractive glass elements, as well as a Neutrino coating, to render imagery with low distortion, controlled spherical and chromatic aberrations, high contrast, and natural color rendering.

In addition to the imaging performance, this 15mm f/2.4 utilizes a manual focus design for fine-tuned control, and incorporates a unique positive focus lock to secure the focusing position at any point for consistent, repeatable shooting. As the Firefly version of this focal length, this lens is also distinguished by a lightweight ABS plastic exterior, printed lens markings, and weather-sealing about the lens housing to permit working in trying environmental conditions.

Pentax K-Mount/Full-Frame Format    Aperture Range: f/2.4 to f/22    Two Aspherical Elements    Two ED and Three HR Elements    Neutrino Coating    Manual Focus Design with Focus Lock    Rubberized Focus Ring    Depth of Field and Focus Distance Scales    Weather-Sealed ABS Plastic Housing    Rounded Nine-Blade Diaphragm

The Firefly version of the 15mm f/2.4 lens features a lightweight ABS plastic exterior construction that is sealed against moisture and dust along the main body of the lens. The Firefly construction also incorporates a rubber focus ring for improved grip and control, and has printed focus distance and depth of field scales to aid working with pre-focusing and hyperfocal focusing techniques.

Wide-angle prime designed for full-frame Pentax K-mount DSLRs, this lens can also be used on APS-C models where it provides a 22.5mm equivalent focal length.

Two aspherical, three high-refractive index, and two extra-low dispersion elements are featured within the optical design to limit both spherical and chromatic aberrations, as well as color fringing and distortion, for improved clarity, sharpness, and even illumination.

A Neutrino coating has been applied to limit lens flare and ghosting for improved contrast and color fidelity.

Manual focus designed is benefitted by a positive focus lock mechanism to secure your focus position at any point to limit unwanted shifting of focus.

A hard click stop indicates the infinity position on the focus ring for easy use in low-visibility conditions.

Large depth of field scale benefits using hyperfocal and pre-focus techniques.

Front of lens has 95mm-diameter filter threads and the rear of the lens accepts 30 x 30mm cut gel filters to lessen the likelihood of vignetting.

Rounded nine-blade diaphragm contributes to smooth bokeh.

Includes complimentary additional rear lens cap.

Related Questions and Answers

Q: 1. What is the difference between the Firefly model and the Blackstone Model? Which would be better with a Canon M-50 with the M to EF/EFS adapter? Can it also be used for landscape photography? Thank you for your time

A: The IRIX 15mm f/2.4 Firefly Lens for Canon EF has a Weather-Sealed ABS Plastic Housing; the Blackstone version has a Weather-Sealed Magnesium Alloy Housing. Either lens will work equally well for landscape photography.

Q: 2. can you use this lens for video?

A: I would think that the IRIX 15mm would be ideally suited to video, especially in industrial situations where one is often restricted in getting a wide field cover shot. This lens could turn a broom closet into a large room.

Q: 3. Will this lense work with Canon RP ?

A: The IRIX 15mm f/2.4 Firefly Lens for Canon EF has a Canon EF mount, while the Canon EOS RP Mirrorless Camera has a Canon RF mount. The lens can be used on the camera with the Canon Mount Adapter EF-EOS R, BH #CAMAEFRF.

Q: 4. Does Pentax K version has aperture confirmation chip?

A: I'm pretty sure this lens is fully manual. However being so wide.. it's not hard to use at all. It has a stop to keep it in focus. It's an amazing lens and one of my favorite from my 10 plus collection.

Q: 5. For the Pentax mount version, will it work with a film Pentax camera like the ZX-5n which has Av and Tv settings or the fully manual K1000 SE? I understand that there is no aperture ring so I would not be able to select the aperture on a fully manual camera like the K1000 and the aperture would default to 22 which would be fine for my intended purpose (landscape photography with a large DoF mounted on a tripod). Was wanting this to use with a K-1 Mk II special for night sky astrophotography landscapes and also be able to use it with my old ZX-5n and a K1000 SE for daytime landscapes. I already have a 95mm night sky light pollution filter - which is why I would prefer this lens over the Roki 14mm 2.8 which won’t accept filters but does have an aperture ring and would likely work fine on my film camera.

A: It will mount to the older Pentax film cameras.

Q: 6. Hi, I use this lens with a canon EOS RP and the EF adaptor. Why is the lens doesn't go down to 2.4, and get stuck at 2.5?

A: The lens should be able to be set to f/2.4 if your lens is focused at infinity. If your lens will not set to f/2.4, there may be an issue with the lens. If the lens was purchased within the last 30 days, you may contact our Customer Service Department to inquire about returning the lens for an exchange or a refund. If you have purchase the lens longer than 30 days ago, as the lens comes with a Limited 5-Year Warranty from the manufacturer, you may contact IRIX directly either by e-mailing them at info@irixlens.com or by calling them at (954) 900-6755.

Q: 7. Can the aperture be controlled by a dead adapter like the FotodioX Pro TLT ROKR Tilt-Shift Adapter for Nikon F Lens to Sony E?

A: The aperture in the IRIX 11mm f/4 Firefly Lens is only controlled electronically. So the Fotodiox tilt/shift adapter would not be able to control the aperture.

Q: 8. Will this lens work on a Nikon D3300?

A: Yes, the IRIX 15mm f/2.4 Firefly Lens for Nikon F is compatible with the Nikon D3300.

Q: 9. will this lens work with the Canon 60D ?

A: It should. It's a full frame lens that should work fine with the Canon 60D. Make sure you get it in the Canon EF mount. Note that it's a Manual focus lens.

Q: 10. Does this lens work on Nikon Z6?

A: I contacted IRIX with your inquiry. They replied that the compatibility of IRIX lenses with Nikon Z cameras (with FZ adapter) has been announced on their Instagram account on October 2018. They state that there are no issues with using IRIX lenses with the Nikon Z cameras using the FTZ lens mount adapter, so you should have no issues using the IRIX 15mm f/2.4 Firefly Lens for Nikon F on the Nikon Z-series Mirrorless Digital Cameras with the FTZ Lens Mount Adapter. The lens' focal length and aperture information will also be transmitted to the camera's EXIF data, along with exposure settings. That being said, do note that this is a manual focus lens, so you will still have to focus the lens manually when using the Nikon FTZ Lens Adapter.