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IRIX 11mm f/4 Firefly Lens for Pentax K

BH #IR11FFP • MFR #IL-11FF-PK
IRIX
IRIX 11mm f/4 Firefly Lens for Pentax K
Key Features
  • Pentax K-Mount/Full-Frame Format
  • Aperture Range: f/4 to f/22
  • Three Aspherical Elements
  • Two ED and Four HR Elements
A versatile ultra-wide prime lens, the Pentax K-mount 11mm f/4 Firefly Lens from Irix balances a sophisticated optical design with a lightweight, durable physical construction. Aspherical, extra-low dispersion, and high-refractive index elements are used to suppress color fringing, chromatic and spherical aberrations, as well as unwanted distortion, and also contribute to producing a high degree of sharpness and clarity. Additionally, a Neutrino coating has been applied to limit lens flare and ghosting for improved contrast and color accuracy when working in strong lighting conditions.
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IRIX 11mm f/4 Firefly Overview

A versatile ultra-wide prime lens, the Pentax K-mount 11mm f/4 Firefly Lens from Irix balances a sophisticated optical design with a lightweight, durable physical construction. Aspherical, extra-low dispersion, and high-refractive index elements are used to suppress color fringing, chromatic and spherical aberrations, as well as unwanted distortion, and also contribute to producing a high degree of sharpness and clarity. Additionally, a Neutrino coating has been applied to limit lens flare and ghosting for improved contrast and color accuracy when working in strong lighting conditions.

In addition to the imaging performance, this 11mm f/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 11mm f/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.
Ultra 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 16.5mm equivalent focal length.
Three aspherical, four 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.
Built-in petal-shaped lens hood blocks stray light in order to reduce lens flare, and also protects the front element of the lens.
Rear of the lens accepts 30 x 30mm cut gel filters.
Rounded nine-blade diaphragm contributes to smooth bokeh.
Includes complimentary additional rear lens cap.

IRIX 11mm f/4 Firefly Specs

Focal Length11mm
Maximum Aperturef/4
Minimum Aperturef/22
Lens MountPentax K
Lens Format CoverageFull-Frame
Angle of View126°
Minimum Focus Distance10.83" / 27.5 cm
Optical Design16 Elements in 10 Groups
Diaphragm Blades9, Rounded
Focus TypeManual Focus
Image StabilizationNo
Filter SizeGel Filter (Rear)
Dimensions (ø x L)4.65 x 4.06" / 118 x 103 mm
Weight1.61 lb / 730 g
Packaging Info
Package Weight3.025 lb
Box Dimensions (LxWxH)6.65 x 5.7 x 5.6"

IRIX 11mm f/4 Firefly Reviews

Great super wide lens

By Dennis
Rated 5 out of 5
Date: 2021-11-30

Great lens for extreme wide angle without the fisheye effect!

Real estate photo must!

By Jordan
Rated 5 out of 5
Date: 2021-05-19

Are used to lean on my canon 16 to 35 for those wide-angle views and I am so happy I found this lens! I was a bit hesitant as it is not "canon" but in very pleased with the results!

Outstanding bargain

By Steven
Rated 5 out of 5
Date: 2021-01-19

My third Irix (have the 15mm in EF and K mount) and its amazing. Smooth focusing, nice feel and features such as focus lock and a detent for infinity, which I use a lot since a super wide rarely needs to be focused anyway, so no concerns about no auto-focus because you don't need it. Only gripe is the lens cap which fits rather loosely, and you wouldn't want to loose it since there,s no front filter threads. And it's a dark lens, or My copy is. Had to comp exposure 1 - 1 1/2 steps, simple fix. Iv'e read that some people have a distortion issue and they must have gotten a bad one because I was blown away with how little, if any distortion with mine (pictures have had NO correction done in post!). Now I want it in EF mount also!

IRIX 11mm f/4 Firefly Lens for Nikon F

By Leonard
Rated 5 out of 5
Date: 2020-11-02

Awesome lens for scenery, landscapes, cramped interiors ... really opens things up! Packaging was excellent, lens was inside a sturdy metal box with heavy duty foam inserts, inside a durable cardboard box, inside a padded cardboard box from B&H. This lens seems very well built, gives sharp images, and has features I wish other lens makers would use in their lenses; the hyper-focal distance scale, click stop infinity detent, and raised 'lever' on focusing ring to name a few. I would definitely recommend this lens as an inexpensive, lightweight, super-ultra-wide-angle lens !!!

Excelent definition !

By Jose
Rated 5 out of 5
Date: 2020-02-09

Excelent sharpeness & definirion. Wife sngle and full straignt lines. Great! Just a little bit big in size & weight in coparison whith Laowa 12 mm f2.8. Both at same level

Unique and useful, produces great results

By Pablo
Rated 5 out of 5
Date: 2019-04-22

I purchased this lens mostly to shoot buildings when the angle of coverage of the 14-24mm is not enough. Image quality is similar to the 14-24mm (some minor distortion in the borders included), aberrations are very easy to fix in Lightroom. Although its not listed in Lightroom, using the Canon profile for this lens works fine. The difference in coverage from 14mm to 11mm is quite substantial. Although this Firefly model is the plasticky weak version, I found it solid and with an excellent construction. You will need a very powerful reason to go for the more expensive and heavier metal  model. Such a wide angle of coverage requires some practice to achieve the results you are looking for, perfectly leveled shooting is a must. Manual focus takes a bit to get used to but closed down to 5.6 or 8 gets a very deep depth of field making critical focus unnecessary. Some criticized the lens cover friction with the lens hood. After several months in use I couldnt find any mark or scratch because of this on the lens hood. Aside of any professional application, photographers in general will find the images produced by this lens very interesting. On top of all, this lens is very affordable and a worthwhile investment.

Ultra wide view can pack a lot in!

By Andrew
Rated 4 out of 5
Date: 2021-11-15

Well made and while not as sharp as my Rokinon 14mm, it's still extremely useful. Stopped down to F11 or F16 with the focus locked on infinity it produces very acceptable images.

Very nice lens

By Jason
Rated 5 out of 5
Date: 2021-07-20

I am surprised by how well built this cheaper Firefly version of the lens is; it feels robust. The images that come out of this lens are sharp even wide open at f/4. Additionally, it's very easy to get your subject in focus with a very long rotation on the focus ring which is also very smooth to turn. I would definitely recommend this lens if one is interested in a very wide angle lens for their full frame camera especially considering it's much cheaper than the Canon 11-24 f/4L lens; as long as you're ok with manually focusing which isn't a problem as 11mm provides a deep depth of field. Overall I'm very happy with this lens.

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YOUR RECENTLY VIEWED ITEMS

Would the Sigma MC-11 adapter for Canon EF to ...

Would the Sigma MC-11 adapter for Canon EF to Sony E mount work on this lens?
Asked by: Tonise
Yes the IRIX 11mm f/4 Firefly Lens for Canon EF compatible with the MC11.
Answered by: Dan
Date published: 2022-03-15

Does this lens work on the FTZ adapter for Nikon ...

Does this lens work on the FTZ adapter for Nikon Z cameras?
Asked by: Anonymous
in a word "Yes" but, works as manual focus only.
Answered by: Jim
Date published: 2019-08-19

Can we get ND filter for this lense ?

Can we get ND filter for this lense ?
Asked by: Shoeb
Yes, But a adapters are needed. Please look into the following item. Cokin Universal X-Pro Series Filter Holder Adapter Ring https://bhpho.to/37clouY Cokin X-Pro Series Filter Holder https://bhpho.to/3C9fTLZ
Answered by: hectorm
Date published: 2021-08-02

What is the difference between Firefly lens vs ...

What is the difference between Firefly lens vs Blackstone lens?
Asked by: larry
Irix 11mm f/4 Firefly and Blackstone share the same specifications. The difference is in the build quality. The blackstone is stronger made of durable aluminum and magnesium alloy. The firefly lens is made of a lightweight ABS plastic exterior construction.
Answered by: Daniel
Date published: 2022-03-17

Is this a fisheye lenses? Thanks

Is this a fisheye lenses? Thanks
Asked by: Shoeb
The IRIX 11mm f/4 Firefly Lens for Canon EF is an ultra-wide-angle lens, but it's not technically a fisheye lens--it doesn't create a circular image and it has been designed to minimize some of the distortion inherent in a lens with a focal length this wide.
Answered by: Boyd
Date published: 2021-08-22

question

Why does this lens have electronics? Is the aperture electronically controlled?
Asked by: Nikolay L.
Per the manual: The lens aperture is operated electronicallythrough the camera.
Answered by: David D.
Date published: 2021-03-20

question

Does this support the manual focus confirmation with recent DSLRs?
Asked by: Michael
Yes, it does.
Answered by: William E H.
Date published: 2018-08-27
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