Irix 15mm f/2.4

Performance Compared Usage

Desert Palms, 13 May 2017. Canon 5DSR, Irix 15mm f/2.4, f/5.6 at 30 seconds at ISO 100. bigger, or full-resolution file to explore on your computer.

The palm trunks and fronds look soft in many places because there was a lot of wind; they were blowing all over the place!

See the tiny white dashes in the sky in the full-resolution file? Those are stars which moved and made short trails in 30 seconds!

Spanish Home, 13 May 2017. Canon 5DSR, Irix 15mm f/2.4, f/2.4 at 1 second at ISO 100. bigger, or camera-original © file to explore on your computer.

Look at the white couch on the left. See the diagonal stripes in the camera-original © file? Those are aliases excited by the fabric and extreme sharpness of this lens — and I shot this wide-open at f/2.4! It's a plain white couch.

Introduction

Performance Compared Usage

B&H Photo - Video - Pro Audio

I buy only from these approved sources. I can't vouch for ads below.

This manual-focus Irix 15mm f/2.4 lens has superb optics, easily the equal or better than the larger, older and more expensive Zeiss 15mm f/2.8.

Irix 15mm f/2.4, Blackstone version for Canon. bigger.

Blackstone (metal) or Firefly (plastic) outsides?

You can get the same great optics in either metal or plastic outer barrels as the Blackstone or Firefly versions.

I'm reviewing the 15mm f/2.4 Blackstone for Canon, which comes in a metal barrel as shown here. The all-metal Blackstone version is very nice, just like a Zeiss 15mm f/2.8

The same optics also come with a plastic outer barrel, called the 15mm f/2.4 Firefly.

The Firefly version (not shown here) has the same optics, the same aluminium internal mechanics and metal mount, but has plastic outsides with a rubber focus ring with a raised bar to let you focus by feel in the dark and has a different case— and weighs less and sells for only 2/3 the price.

Which you prefer depends on your budget for money and for weight; it's the same lens inside.

If weight isn't a concern, see Is It Worth It.

Format

Performance Compared Usage

This is a full frame (FX) lens, and I'll be reviewing it as such.

It works great on DX cameras, too, on which you may make the usual inferences, but you're wasting most of this lens' performance shot on a small frame camera.

Use the Canon 10-18mm or the Nikon 10-24mm for better performance for less money on APS-C cameras. This is a full-frame lens and should be used on full-frame cameras.

Compatibility

Performance Compared Usage

Canon

I have the Canon version and am reviewing it here.

Other other than being manual focus, it has all the proper electronic contacts for complete interface and communication with all Canon EOS 35mm and digital cameras made since 1987.

Nikon

The Nikon version should work great with every FX digital Nikon.

It has a chip that should let it work in all metering modes and in all P, S, A, and M exposure modes, just like Nikon's AI-P manual-focus lenses.

It is a "G" lens with no aperture ring, so it won't work on manual-focus 35mm Nikons from before about the F4 of 1984.

See Nikon Lens Compatibility and look down "G" column for details with your camera.

Specifications

Performance Compared Usage

Names

Irix calls this the Irix 15mm f/2.4 Blackstone, or the plastic barreled version as the Irix 15mm f/2.4 Firefly.

I'm reviewing the Blackstone version for Canon. The other versions have the same optics.

Optics

Irix 15mm f/2.4 Internal Optical Construction. bigger.

15 elements in 11 groups.

2 aspherical elements.

2 extra low dispersion elements.

3 high refractive-index elements.

Multicoated; branded as "neutrino."

Rear focussing.

Diaphragm

Irix 15mm f/2.4 at f/2.4; diaphragm not visible. bigger.

9 rounded blades.

Stops down to f/22.

Focal Length

15 mm.

When used on APS-C cameras, it sees the same angle of view as a 24 mm lens sees when used on a 35mm or full-frame camera.

Autofocus

None; Manual focus only.

Infinity Focus Stop

No; just a mild click stop.

Probably miscalibrated.

Close Focus

0.8 feet (0.25 meters).

Filters

Front: Metal 95 mm filter thread.

Rear: 30 × 30mm gelatin slot.

Hood

Irix 15mm f/2.4, Blackstone version for Canon. bigger.

Plastic bayonet ILH-15A hood, included.

Sliding access hole to rotate filters with hood attached.

Case

Irix 15mm f/2.4 Blackstone included case. bigger.

Sculpted semi-hard case included.

Size

3.94" maximum diameter × 3.31" extension from flange.

100 mm maximum diameter × 84 mm extension from flange.

Weight

22.625 oz. (641.5 g) actual measured weight, lens only, Canon Blackstone.

23.765 oz. (673.75 g) with included hood as shown.

Irix specifies:

Firefly

Blackstone

Canon

608 g.

21.4 oz.

685 g.

24.2 oz.

Nikon

581 g.

20.5 oz.

653 g.

23.0 oz.

Announced

January 2016.

Included

Irix 15mm f/2.4 Blackstone packaging. bigger.

Fancy metal box holding paperwork.

Lens.

Front and rear caps.

Spare rear cap.

Hood.

Case.

Irix 15mm f/2.4, Blackstone version for Canon with included caps and hood. bigger.

Quality

Made in Korea.

Price, USA

April 2018: $675 in metal "Blackstone" barrel; $425 with plastic "Firefly" outer barrel.

May 2017: $599 in metal "Blackstone" barrel; $399 with plastic "Firefly" outer barrel.

Irix 15mm f/2.4 Blackstone. bigger.

Performance

Performance Compared Usage

Overall Autofocus Manual Focus

Focus Calibration Breathing Bokeh

Distortion Ergonomics Falloff Filters

Flare & Ghosts Lateral Color Fringes

Macro Mechanical Quality

Sharpness Sunstars

Overall

The Irix 15mm f/2.4 has great optics, but watch out for sloppy focus ring calibration from the factory.

Autofocus

NONE.

Manual focus only.

Manual Focus

performance top

Manual focus is stiff; it takes two fingers to move the ring.

There is a locking ring in front of the focus ring to lock focus.

Focus Calibration

performance top

Irix 15mm f/2.4, Blackstone version for Canon. bigger.

Like most other Korean-made lenses I've reviewed, the infinity focus calibration of my sample oddly is a little off. On my sample I have to focus past infinity until the infinity mark is at f/11 to focus properly at infinity. Yours will be different, and hopefully perfect.

There is an access cover to allow you to fine-tune this yourself, but it's sad that not every Korean lens arrives perfectly calibrated as Nikon's, Canon's and Pentax' manual-focus lenses always are. Manual focus lenses all should be perfectly calibrated at the factory, where they should have the correct equipment (a laser interferometer and a very precisely and calibrated jig) to do this. There is no excuse for any lens arriving out of adjustment, and once adjusted, manual focus lenses will stay in adjustment for a lifetime or more.

All my Nikon, Canon and LEICA manual-focus lenses from the 1930s, 1940s, 1950s, 1960s, 1970s and 1980s are still in perfect adjustment since being manufactured. These don't drift, and it is the factory's responsibility, not ours, to get this right the first time.

If you do dare to tweak this yourself, there are instructions on page 9 of Irix' 15mm Blackstone User's Manual, but watch out: it warns not to lose the little screws you have to remove inside the lens and suggests a magnetic screwdriver to prevent this. That's enough to scare me; I won't attempt this adjustment myself. Others have done this just fine.

For a $1,400 savings over the Zeiss 15mm f/2.8 I'm not worrying about this. All I do is tape a new focus index mark at the correct location and I'm good for focussing by scale — or it makes no difference at all in Live View.

Focus Breathing

Focus breathing is the image changing size as focused in and out. It's important to cinematographers because it looks funny if the image changes size as focus gets pulled back and forth between actors. If the lens does this, the image "breathes" by growing and contracting slightly as the dialog goes back and forth.

There is very little breathing. The image may grow slightly as focussed more closely, but I doubt it will be visible.

Bokeh

Bokeh, the feel or quality of out-of-focus areas as opposed to how far out of focus they are, is surprisingly pleasant. It's just soft, and not busy.

Bokeh isn't very important with a 15mm lens because its huge depth of field means almost nothing is ever out of focus in the first place.

Here's a sample at f/2.4 at headshot distance:

Davis 6250 weather station, 15 May 2017. bigger or camera-original © file to explore on your computer (mobile devices rarely display full resolutions images properly).

Distortion

Distortion is less than most ultrawide lenses, and even better, it's easy to correct with a value of +2.50 (at 3 meters/10 feet) in Photoshop's lens distortion filter.

Most other ultrawides have more distortion, or have complex distortion not easily corrected later.

The distortion is mild to moderate barrel, which is rarely visible. Here is an uncorrected sample:

Desert Entryway, 13 May 2017. Canon 5DSR, Irix 15mm f/2.4, f/5.6 at 1/40 at ISO 100. bigger, or full-resolution file to explore on your computer.

Looks good to me!

Here's Irix' data:

Ergonomics

Irix 15mm f/2.4, Blackstone version for Canon. bigger.

This is a heavy metal lens.

The focus ring is stiff, requiring a strong grasp to twist quickly.

Yes, the focus ring grip is slightly curved. No big deal; it tends to keep your fingers from sliding forward or back off the fluting.

There is also a focus lock ring, but I have no idea why you'd need it with focus as stiff as it is. It feels similar to the Zeiss 15mm f/2.8.

The mounting index dot is a nearly invisible small grey dot; it should be a big red plastic blob you can feel in the dark — but no!

The all-white markings would be much more useful if they were color-coded: red infra-red index, yellow footages, etc.

Falloff

Falloff on Full Frame and 35mm is moderate at f/2.4, and mostly gone by f/4 and f/5.6.

Since it's a third-party lens, you camera won't be able to correct it with a lens profile.

I've greatly exaggerated the falloff by shooting a gray field and placing these on a gray background:

Falloff on Full-Frame and 35mm at infinity, no correction.

f/2.4	f/2.8


f/4	f/5.6

Filters, use with

performance top

Use thin filters. A thick 95mm filter will vignette a little on full-frame.

Don't use polarizers on ultrawide lenses; the sky's natural polarization will appear as a dark band in the sky.

Flare & Ghosts

Flare and ghosts are nearly nonexistent:

Ghosts and Flare at f/2.4, 15 May 2017. Canon 5DSR, Irix 15mm f/2.4, f/2.4 at 1/1,000 at ISO 100. bigger, or camera-original © file to explore on your computer.

There is nearly none wide-open, which is superb.

Stopped down you'll see just a little if you really push it as I've done here, with the full daytime disc of the sun in one part of the image and then a dark tree in the rest of the image, and then add extra exposure as I've done here to to exaggerate it:

Ghosts and Flare at f/8, 15 May 2017. Canon 5DSR, Irix 15mm f/2.4, f/8 at 1/100 at ISO 100. bigger, or camera-original © file to explore on your computer.

See more at Sunstars.

Lateral Color Fringes

There are nearly no color fringes as shot on my 50 MP Canon 5DSR without a lens profile, which is superb performance.

Nikon cameras will automatically correct what little there is, and even on my uncorrected Canon 5DSR I can see only very slight red/blue lateral color on extreme tests; there is none with any sort of real photo.

This is magnificent!

Macro

If focuses to within inches of the front of the lens, but since it's so wide, doesn't look like it's that close:

Kienzle Flieger Automat 800/2843, 12 May 2017. Full-frame Canon 5DSR, Irix 15mm f/2.4 at close-focus distance, f/2.4 at 1/1,600 at ISO 100. bigger, or camera-original © file to explore on your computer.

1,200 × 900 pixel crop from above. bigger, or camera-original © file to explore on your computer. Yes, you're seeing dust on the watch face.

If this crop is about 6" (15cm) wide on your screen, then the complete image printed at this same extreme magnification would be about 20 x 30" (50 x 75cm).

If this crop is about 12" (30cm) wide on your screen, then the complete image printed at this same extreme magnification would be about 40 x 60" (1 x 1.5 meters).

Wow! Even shot wide-open at f/2.4, it's ultra sharp and contrasty at every focus distance.

Mechanical Quality

Irix 15mm f/2.4, Blackstone version for Canon. bigger.

It's well made mechanically; it's all metal. The bad part is that my sample had poor focus calibration making the focus scale relatively useless, but the mechanics are sturdy and likely to live a long time.

Irix says this Blackstone version has a magnesium alloy barrel; but it feels just like the usual anodized aluminum.

Hood

Plastic bayonet.

Front Bumper

None.

Filter Threads

Metal.

Hood Bayonet Mount

Metal.

Front Barrel

Metal.

Focus Ring

Metal.

Rear Barrel

Metal.

Identity

Engraved on front barrel.

Internals

Seem like all metal!

Moisture Seal at Mount

Yes.

Mount

Dull chromed metal.

Markings

Mostly engraved and filled with paint.

Serial Number

Laser engraved in black towards back of barrel.

Date Code

None found.

Noises When Shaken

very mild clicking.

Made in

Korea.

Sharpness

The only limitations are your skill as a photographer and the lenses you use.

This lens, like most major-brand lenses introduced since 2010, is ultra sharp.

It may be the sharpest fixed ultra-ultrawide lens I've ever tested. It's ultrasharp and contrasty and devoid of spherical aberration and lateral color throughout the whole image even wide-open at f/2.4. The only slight imperfection is that it is slightly softer in the last few millimeters of the full-frame corners at f/2.4, but even there it becomes ultrasharp as soon as stopped down a little.

It's so sharp and contrasty that it can incite aliasing on a 50 MP Canon 5DSR, even shot wide-open!

Look at the white couch on the left. See the diagonal stripes in the camera-original © file? Those are aliases excited by the fabric and extreme sharpness of this lens, not stripes on the couch!

Spanish Home, 13 May 2017. Canon 5DSR, Irix 15mm f/2.4, f/2.4 at 1 second at ISO 100. bigger, or camera-original © file to explore on your computer.

Here is Irix' MTF chart:

MTF chart.

Note that this is an MTF chart in the format most used by lens designers that plots the lens' response at four picture angles versus spatial frequency. Most marketing charts plot MTF by field angle for a few spatial frequencies.

Sunstars

More good news is even though it has a rounded diaphragm, the Irix 15mm can make 18-pointed sunstars on brilliant points of light at the smaller apertures.

Click any of these to enlarge:

Compared

Performance Compared Usage

Overall

This Irix 15mm has optics as good or better optically than any of these lenses below and takes normal filters, which most of the other lenses do not.

It's also by far the least expensive of any of these.

The disadvantage is that it's only manual focus, and that your sample may not focus at infinity exactly at the infinity click.

Canon 11-24mm

This lens is the world's standard: ultra sharp and ultra-ultra wide.

If you can afford the price, size and weight, get the Canon 11-24mm, but know that you can't use front screw-in filters with it as you can with the Irix 15mm.

Laowa 12mm f/2.8

This 12mm lens is significantly wider, but it costs more and has zero electronic compatibility on Canon.

You can't use filters on this 12mm lens.

Nikon 13mm f/5.6

The Nikon 13mm is Nikon's widest. It sells for about $30,000 used in 2017, if you can find one.

The 13mm is much, much slower, bigger and heavier and takes only rear bayonet filters, but it is wider and has less distortion

Canon 14mm f/2.8L

The Canon 14mm L was from film days, and is nowhere near as sharp as this Irix lens. The Canon 14mm only uses rear gel filters, but it does autofocus.

Canon 14mm f/2.8L II

Sadly the new Canon 14mm lens isn't much sharper than the old one; this Irix lens is much sharper at large apertures — and the Irix lens takes normal filters.

Nikon 14mm f/2.8 AF-D

This older Nikon lens can't use front filters, and is much less sharp in the corners wide open and has more distortion— but it does autofocus and is wider.

Nikon 14-24mm f/2.8 G

Nikon's state of the art and it goes wider, but it's big and heavy and has more distortion and can't use front filters.

Nikon 15mm f/5.6

This is a 1970s manual focus lens about the same size as this Irix, but lacks the speed and optical performance, and can't use front filters.

Nikon 15mm f/3.5 AI-s

This is a newer 1970s manual focus lens about the same size as this Irix, but lacks the speed and optical performance, and can't use front filters.

Zeiss 15mm f/2.8

This is a larger lens and has the advantage of also taking 95mm front filters, but it costs over three times as much for about the same optical quality.

Canon 16-35mm f/4 L IS

This is Canon's most practical ultrawide, reasonably priced, takes normal filters and has stabilization with superb optics — but it's not quite as wide as the Irix 15mm.

Nikon 16-35mm f/4 VR

This is Nikon's most practical ultrawide, reasonably priced, takes normal filters and has stabilization with superb optics — but it's not quite as wide as the Irix 15mm.

Usage

Performance Compared Usage

f/2.4?

This lens is f/2.4, which is a half-stop faster than f/2.8.

Since Nikon and Canon cameras usually are set to work in third stops, sometimes they will show this lens as f/2.5, which is a third stop faster than f/2.8.

Potato, potatoe. Ignore this; f/2.5 is the same as f/2.4 as far as photography is concerned.

Lens Hood

The hood can mount four ways, but only two ways are correct.

The other two will be 90º off and you'll have dark left and right image sides, with a square image in the center.

Be sure the hood is mounted so the long parts of the hood are on top and bottom, not left and right.

Focus

I focus manual ultra-ultrawide SLR lenses by scale: I guess at the distance, and set it on the focus ring. It's usually more accurate than using focus aids through an SLR's viewfinder.

Live View at f/2.4 is the most accurate.

Recommendations

Performance Compared Usage

This is a great 15mm lens at a bargain price and much nicer than anything else I've ever seen out of Korea. If you're in the market for a fixed 15mm ultra ultrawide, this is probably your best buy.

Filters

Protection

I'd use a 95mm B+W MRC 010 UV filter to protect this lens.

A better filter for twice the price is the 95mm Hoya EVO UV. It has special dirt, dust and smudge resistant multicoatings to stay cleaner longer.

Grads and ND

I use Tiffen HT grads because they are the only truly neutral NDs and grads I've used, they are multicoated and thin enough not to vignette.

Polarizers

Don't use polarizers on ultrawide lenses; the sky's natural polarization will appear as a dark band in the sky.

Where to get yours

I'd get it at Adorama, at Amazon or at B&H.

This all-content, junk-free website's biggest source of support is when you use those or any of these links to approved sources when you get anything, regardless of the country in which you live. Irix does not seal its boxes in any way, so never buy at retail or any other source not on my personally approved list since you'll have no way of knowing if you're missing accessories, getting a defective, damaged, returned, store demo or used lens. I use the stores I do because they ship from secure remote warehouses where no one gets to touch your new camera before you do. Buy only from the approved sources I use myself for the best prices, service, return policies and selection.

Thanks for helping me help you!

Ken, Mrs. Rockwell, Ryan and Katie.

More Information

Performance Compared Usage