Irix 11mm F4 Firefly & Blackstone

Construction and Handling

As would be expected of an extreme wide angle, the Irix 11mm F4 is large. It is saved in part by the moderately fast aperture.

This section will give you a complete tour of the lens, from every angle. You will also see the lens alongside other comparable lenses and mounted on various camera bodies. We will take a look at both the Firefly and Blackstone versions, highlighting the differences when they occur. The lens looks a lot like the Irix 15mm; some of our comments from that review are repeated here.

Front Element

The front of the lens is dominated by the large piece of glass covering most of the surface. It is surrounded by a small amount of plastic which reaches up to the hood. There are no markings on the front.

The company brands its coatings “Neutrino coatings”. While they do not elaborate on this, it can be safely assumed that it is a multi-coating as is the standard in the industry.

As can be expected, the glass is strongly convex, preventing the use of regular filters. Irix does offer their system of filters which are meant to be used with this lens.

While not externally apparent, the front element hides a difference between the Firefly and Blackstone. The latter includes weather resistant seals on the front, which the former lacks.

An innovative feature of the lens is the inclusion of a slot on the back of the lens. This accommodates square 30x30mm gelatin filters. It will not work for a polarizer, obviously, but will function flawlessly for colored or neutral density filters. The manual even includes a template to cut gel sheets to the right size. The same slot is found on the 15mm F2.4.

The lens cap is huge and thick. Made of plastic, it covers the entire hood and attaches to the hood. This brings us to one of the few mechanical flaws we found on the 11mm: on our samples, the machining left some plastic residue on the hood's attachment points. A minor detail, but surprising.

Lens Body

While there are many similarities between the Firefly and Blackstone, a quick glance is enough to spot the main differences. They are the same as on the company's 15mm lens.

The Firefly’s outer shell is made of plastic. In this case, the Firefly is 8% lighter than the magnesium-aluminum alloy of the Blackstone. Even with its plastic body, the Firefly offers a high-quality finish; there is nothing cheap about it. It has a good heft, is tightly assembled and feels rugged. The type of plastic used feels high-grade and its texture is pleasing.

The Blackstone is just as well made and appears even more premium. The lettering is engraved instead of printed, which yields an off/white color (instead of the pure white of the Firefly). The metal alloy is visible and immediately felt on touch. It is smoother, shinier and subjectively feels nicer. Metal is used everywhere except at the front and on the focus ring.

The lettering is said to be “fluorescent”, which could lead some users to assume it glows in the dark (which would be a VERY clever idea but would be called “phosphorescent”). In fact, the lettering only reacts to UV light, which makes its usefulness very limited. It won’t glow if there is no UV light around, akin to a white shirt under a “blacklight”. It also won’t retain any illuminating power when the light is turned off (like what would happen with watch hands, for instance).

Both lenses have the same general body shape, with one specific exception on the focus ring. The lens tapers out from the mount and takes a mostly cylindrical shape going from there. There is no aperture ring.

The first element above the mount is an alignment dot and the “neutrino coating” label. Immediately above is the focus distance scale, with markings for F4, F8, F11 and F16. This is a lot of information, and rather useful given the lens' often large depth of field. There is also a reference for IR photography, a nice inclusion. The focus ring is obviously next. As is usual, it includes markings in meters and feet. What is less common is the detailed hyperfocal information. Again, the lens includes markings for F4, F8, F11 and F16. With such a wide angle, hyperfocal is likely to be used often; these markings will prove useful for many photographers.

The focus ring itself differs between the two versions: ribbed on the Blackstone, dotted and with a notch on the Firefly. In both cases, it is 3.3cm wide. We will comment further on the focusing page. The Firefly also repeats the “neutrino” label on its focus ring, something the more streamlined Blackstone omits.

Next is the focus lock ring (0.9 cm wide), standing immediately above the focus ring. The lens then flares out and bold lettering displays the name and aperture. Last is the hood, bearing the Irix name in modern lettering.

The back of the lens displays the filter diameter at the top, next to the infinity adjustment access. Subdued lettering at the bottom shows the CE and FCC markings, the manufacturer name and the label “Swiss design – Made in Korea”.

As seen from the side, the front element's bulbous shape is obvious.

Aperture

The Irix 11mm uses 9 rounded aperture blades.

Lens Mount

The lens mount is metal. Although not as apparent as Pentax’s red o-ring, the lens does offer weather seals on the mount, for both versions. As mentioned earlier, the back of the lens includes a window meant for gel filters.

Lens Hood

The lens hood is the same for both the Firefly and the Blackstone. It is a huge hood, mostly because of its width, and permanently attached to the lens. It serves, in part, to protect the protruding front element.

Compared to Other Lenses

Here is the Irix 11mm next to the Pentax DA 16-85mm and FA 43mm lenses, and next to the Irix 15mm, with and without the hood for the 15mm.

The 11mm is many times larger than the 43mm. With its hood, it is also longer than the 16-85mm, but wouldn't be if the latter also had the hood on. It is much larger however.

The comparison with the Irix 15mm is interesting. While the expectation would be for the wider focal length to be larger, they are in fact almost identical up to the lens hood, there the wider maximum aperture of the 15mm requires a wider hood. The appearance of the lens shaft shows that Irix kept the exact same design language for both lenses.

Mounted on Camera

Below are images of the 11mm mounted on a Pentax K-1 (full frame) and a Pentax K-3 (APS-C). The lens is right at home on the K-1, and a little large but not out of place on the K-3.

Verdict

Like its 15mm sibling, the Irix 11mm is nicely assembled. The attention to details, the numerous controls and the amount of printed information is commendable. Both the Firefly and Blackstone are beautiful lenses with few design flaws. While the Blackstone does feel more premium, the differences between the two versions are not as important as one could expect. If one needs full weather sealing, the Blackstone is the obvious choice. The Firefly offers enough seals to protect the camera body, but the lack of protection at the front means that it should not be used in difficult conditions. If WR is not needed, there is little reason to pay a higher price for the more expensive version.