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IRIX 15mm f/2.4 Firefly Lens for Pentax K

BH #IR15FFP • MFR #IL-15FF-PK
IRIX
IRIX 15mm f/2.4 Firefly Lens for Pentax K
Key Features
  • Pentax K-Mount/Full-Frame Format
  • Aperture Range: f/2.4 to f/22
  • Two Aspherical Elements
  • Two ED and Three HR Elements
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.
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IRIX 15mm f/2.4 Firefly Overview

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.

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.

IRIX 15mm f/2.4 Firefly Specs

Focal Length15mm
Maximum Aperturef/2.4
Minimum Aperturef/22
Lens MountPentax K
Lens Format CoverageFull-Frame
Angle of View110°
Minimum Focus Distance11.02" / 28 cm
Optical Design15 Elements in 11 Groups
Diaphragm Blades9, Rounded
Focus TypeManual Focus
Image StabilizationNo
Filter Size95 mm (Front)
Gel Filter (Rear)
Dimensions (ø x L)4.49 x 3.94" / 114 x 100 mm
Weight1.28 lb / 581 g
Packaging Info
Package Weight2.55 lb
Box Dimensions (LxWxH)6.6 x 5.5 x 5.4"

IRIX 15mm f/2.4 Firefly Reviews

Brilliant Sharpness

By Gerard
Rated 4 out of 5
Date: 2022-01-05

So far I have used this lens on a few shoots. It definitely surpassed my Rokinon 14mm in sharpness and quality for not much more money.

Great lens for the money.

By Dwayne
Rated 5 out of 5
Date: 2021-07-13

I use this lens for Astro and having the indent for infinity focus works great.

Well balanced Irix lens

By Colin
Rated 5 out of 5
Date: 2021-06-22

I've had this lens for a while now, and it is both truly rectilinear, sharp, and comfortable in the hand. It's wide! Much more angle and you'll be photographing your feet. There are electronic contacts for Nikon cameras, and the infinity focus point could be adjusted. One suggestion I'd make with big, fast lenses, is to consider an ND4 filter so as to keep shutter speeds manageable.

Amazing lens

By Rikky
Rated 5 out of 5
Date: 2021-05-09

Used with my Nikon D850, noticed no vignetting, photos are tack sharp. The lens gives a great bokeh when wide open. Infinity focus is right on and the focal locking ring is a great feature. The lens is very well built and is akin to a Zeiss lens at a fraction of the cost. You can also get beautiful lens flare and sun flares with ease.

Great Wide Angle Lens

By Oey
Rated 5 out of 5
Date: 2021-11-15

great lens. affordable and able to get great results.

Great value

By Neil
Rated 5 out of 5
Date: 2021-10-18

Bought this for landscape and Astrophotography. I've been pleased. Only con thus far is the lens hood can be tough to click on and off and the lens cover is par and with most lens. Again a great value for the performance. Shooting on a Canon 5DSR with tripod and Internal ND filters.

good value

By Bodie
Rated 4 out of 5
Date: 2021-07-30

light and crispy, perfect for rollers

Solid choice for night sky photography

By Teresa
Rated 5 out of 5
Date: 2021-07-26

This lens, which I bought expressly for night-sky photography, captures a wide swath of the sky. There is distortion of any straight objects in the photo (for example, if a building is shown in the foreground) but that is to be expected with this super-wide lens. Minimal coma in the corners, which is an issue I've had with other wide-angle lenses. And best of all... the infinity setting really IS infinity, and it has a click-stop so I know when I've hit it in the dark. I have this same lens for my Canon 6D (also used for night-sky photography) and the fact that I bought one for my new Pentax should make it clear how much I like this lens.

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YOUR RECENTLY VIEWED ITEMS

For the Pentax mount version, will it work with a ...

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.
Asked by: Roy
It will mount to the older Pentax film cameras.
Answered by: Patrick
Date published: 2020-07-09

Do this lens have Sony e mount?

Do this lens have Sony e mount?
Asked by: Anonymous
Unfortunately for the time being there isn't one.
Answered by: Ryan
Date published: 2021-08-26

¿Funcionará esta lente con la Canon EOS 800D?

¿Funcionará esta lente con la Canon EOS 800D?
Asked by: Victor
Este lente si es compatible con su camara EOS 800D (T7i)
Answered by: Luz
Date published: 2022-01-10

Does this lens work on Nikon Z6?

Does this lens work on Nikon Z6?
Asked by: Wassim
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.
Answered by: Manzell
Date published: 2021-09-10

Hi, I use this lens with a canon EOS RP and the ...

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?
Asked by: Nicolas
I have similar setup (EOS r) and see same but I do not find the lens is “stuck”. When canon reports it at f2.5, the lens is wide open. And IRIX rates this lens at f2.4 which is a mathematical result of focal length and aperture diameter. Canon reports f stop numbers in 1/3 increments (typical setup). 2.5 is 2/3 of stop between f2 and 2.8. This is same on all Canon EOS camera.
Answered by: David
Date published: 2021-03-24

question

Does this lens have an aperture ring that can be turned by hand?
Asked by: Matthew
Happy to help. I bought the Irix Blackstone 15 mm f2.4 for Nikon, but I believe the Blackstone is the same as the Firefly. No there is NOT an aperture ring to turn. The aperture and shutter speed are set as one likes in manual mode, by twisting dials on the body of the camera. Of course the focus ring on the lens itself can be turned by hand. Best wishes.
Answered by: Paul H.
Date published: 2019-05-25

question

Does Pentax K version has aperture confirmation chip?
Asked by: Miguel
Since the nikon and canon version has both no external aperture ring and both are electronic, im pretty sure that pentax, sony and all the other have the same systeme.
Answered by: Joel G.
Date published: 2018-08-27

question

will this lens work with the Canon 60D ?
Asked by: Sean M.
Yes this lens will work on a Canon 60D, however because of the crop sensor in this camera the lens will more like a 24mm rather than 15mm.
Answered by: John H.
Date published: 2018-08-27
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