Canon 24mm f/2.8 STM
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Canon 24 2.8 STM.
Can you see it on this 7D Mark II? It's this small!
Sample Image Files
The Canon EF-s 24mm f/2.8 STM is a tiny and super-sharp normal to wide lens for Canon's APS-C cameras. It makes an excellent replacement for any 18-55mm zoom, saving size and weight and adding a fast f/2.8 speed for use in dim light and making your viewfinder brighter. It's tiny, and has fantastic performance.
This 24mm lens sees the same angle of view on an APS-C camera as a 35mm lens sees on full-frame.
It is smaller than many lens caps. Put its caps on, and it's twice the size!
The 24/2.8 STM uses a new kind of autofocus motor, called STM (stepper motor) for quieter AF, and is especially intended for use while shooting video with a DSLR. This motor makes only the lightest humming sound as it focuses.
There is immediate manual-focus override simply by turning the front ring. It's done electronically, and unlike almost all other electronically-focussed lenses, this Canon manual-focus system works great. It's the smoothest, lightest manual focus system ever — even better than any lens from LEICA, hah!
The optics of this lens are superb, and its size make it a complete winner. For $150, you can't go wrong.
Compatibility and Formats
Canon calls this the CANON LENS EF-S 24mm f/2.8 STM.
EF means "electronic focus," meaning that there is an autofocus motor in the lens itself. All Canon lenses since 1987 have been EF.
-s means "small format," meaning that this lens only works or mounts on Canon's APS-C DSLRs.
STM means that the AF motor is a stepper motor.
∅52: 52mm filter thread.
6 elements in 5 groups.
One aspherical element, shown in green.
Muliticoated mostly in magenta and green.
Used on a 1.6x camera, it will see about the same field of view as a 35mm lens sees on full-frame.
Angles of View
Close Focus top
0.52 feet (6" or 0.16 m) from the image plane, specified.
Maximum Reproduction Ratio top
With EF12 II tube: 1:1.3 (0.77x).
With EF25 II tube: 1:0.72 (1.38x, bigger than life size).
Front, Canon 24/2.8 STM at f/2.8 (EF diaphragm not visible).
7 rounded blades.
Stops down to f/22.
Reasonably round to f/8, heptagonal from f/11 to f/22.
Focus Scale top
The ring turns without stops; it's just an electronic encoder.
Depth-of-Field Scale top
Infra-Red Focus Indices top
52mm thread, plastic.
Does not rotate, but moves in and out with focusing.
Canon specifies 2.7" (68.2 mm) diameter by 0.9" (22.8 mm) extension from flange.
Canon says to add 23.9mm if you want the overall length with caps.
4.190 oz. (118.8 g), measured.
Canon specifies 4.4 oz. (125 g).
Plastic screw-in ES-52, optional.
I wouldn't bother with it.
LP811 sack, $24.
I'd use a tube sock instead.
Canon EF-s 24mm f/2.8 STM with included caps.
Standard 52mm E-52 II front cap.
Standard EOS cap rear.
Made in Malaysia.
Photokina, September 2014.
Canon Model Number top
Canon Product Code top
9522B002. (9522B001 in Japan).
JAN Code top
Price, USA top
2015 April: $149.
2015 January: $150.
Box, Canon EF-s 24mm f/2.8 STM.
The Canon 24mm f/2.8 STM is as tiny as the tiniest lens ever made by Canon, the 40mm STM, and is even lighter. This is Canon's lightest lens of all time; lighter even than the 50/1.8 II.
This tiny 24mm lens is optically wonderful as well.
Autofocus speed is moderate.
It's not quite as fast as other Canon lenses, but it's quieter so you won't hear it as much while shooting movies.
Like all wide lenses, its AF speed is more than fast enough to catch fast action:
Just grab the focus ring for instant manual-focus override in ONE SHOT mode. In AI SERVO, the camera will keep trying to focus for you.
You never need to touch the AF-MF switch unless you want to lock-out autofocus.
AF is quieter than most Canon EF lenses.
It makes a quiet, precise hum as it moves, then no sound when it's in focus.
When the lens is constantly moving in and out in AI SERVO mode for video, it is quieter than other USM lenses since it doesn't make mild banging noises as it reverses direction.
AF Accuracy and Consistency
AF accuracy is dead-on on my Canon 7D Mark II.
At f/2.8, this isn't very difficult.
Manual focus works great; the electronic system works better than any other similar system.
There's no hesitation when turning the ring, and it works very quietly as well.
Focus breathing is of interest to cinematographers who don't want the image changing size ("breathing") as the lens is focused among different subjects.
The image of the Canon 24mm f/2.8 STM gets larger as focused more closely.
Shot with Canon 24mm f/2.8 at f/2.8. Camera-original © file.
Bokeh is smooth, but nothing ever gets much out focus with a 24mm f/2.8 lens.
If you want to lose a background, use a longer lens like the 40mm STM or any tele.
The color balance of this 24mm f/2.8 matches my other Canon EF lenses.
This Canon 24/2.8 STM has mild barrel distortion that gets slightly stronger at very close distances.
It will go away when used on a camera like the 7D Mk II is used with a lens profile, and is easy to correct in Photoshop's Lens Correction Filter with these values. This isn't data; these are the results of much field research and calculation on my part:
© 2015 KenRockwell.com. All rights reserved.
Canon 24/2.8 STM.
Ergonomics are perfect; just grab and go.
Shot without a lens profile, there is mild to moderate falloff at f/2.8, which goes away by f/4.
I've greatly exaggerated this below by shooting a flat gray target and presenting these images against a flat gray background:
Use a lens profile in your camera and of course this goes away.
52mm is a huge filter size for the tiny optics of this lens.
It works without vignetting with many stacked filters, but watch it: Canon cautions to use just one so you don't damage the wimpy internal mechanics of the focus mechanism.
The 24 STM has no visible ghosts, and I shoot it with a multicoated UV filter.
This is as bad as I could make it look, and this is with a multi-coated Nikon L37c (370 nm UV) filter over the lens:
Streetlamp with moon, 28 January 2015. (Canon 7D Mk II at Auto ISO 400, Canon 24mm f/2.8 STM with Nikon L37c filter, f/2.8 at 1/30 hand-held, no lens profile, Perfectly Clear V2.) full-resolution file.
The little white dot in the tree below the street light is the moon, not a ghost.
I am able to get one slight dot opposite a bright source of light if the source is closer to the center:
There are some very slight red-blue color fringes when shot without a lens profile.
These won't be visible in actual pictures, and go away with a lens profile.
This lens gets to within just a few inches of the subject:
Crop from above image at 100%, 20 MP Canon 7D Mark II. If this is about 6" (15cm) on your screen, printing the complete image at this same high magnification would result in a 40 x 60" (100 x 150 cm) print!
This is a 60-year-old watch, and you can see all the crud in explicit detail.
It will not work with tele-extenders.
Canon also cautions not to use close-up lenses, since they weigh enough to mess up the focus system.
It's super sharp at all apertures. Only at macro distances there is a bit of spherical aberration wide-open at f/2.8 which leads to slightly lower contrast, with a sharp core under the slight veiling haze. At f/4, it's perfect as you can see above.
Rear, Canon 24 f/2.8 STM.
The Canon 24mm f/2.8 STM is a decent lens, made entirely of plastic, with a metal mount. Since the mount is half the lens, it feels pretty tough, even if the internal mechanism may not be.
None, you use the filter threads.
Seem like all plastic.
Moisture seal at mount
White plastic bump.
Bottom, Canon EF-s 24mm f/2.8 STM.
Laser-engraved into bottom of lens barrel.
Noises When Shaken
This Canon 24 is so sharp that if you can't make a sharp picture with it, you're doing something wrong. Most of the newest lenses from Canon and Nikon are this good; it's not like the old days of the 1990s and before when there could be sharpness differences between lenses.
This is with no lens profile: no correction for fall-off or lateral color fringes, and this lens is still super-sharp out to the edges.
It's diffraction-limited by f/5.6, meaning this lens is just about perfect. f/5.6 is its sharpest aperture, and diffraction starts dulling the image by f/8.
Here is Canon's rated MTF curve, which agrees that it's sharper at f/2.8 than at f/8:
Canon USA 24mm f/2.8 STM MTF: 10 and 30 cycles., f/2.8 and f/8.
With a rounded 7-bladed diaphragm, sunstars have diffuse, not sharp, points.
For the best sunstars, shoot at f/11 or smaller.
There isn't much to compare.
Every other lens is much, much bigger and more expensive, and not any sharper.
There is no sharper 24mm lens for Canon APS-C cameras. For ten times the price, the Canon 24mm f/1.4 II is faster, tougher and covers full-frame, but isn't quite as sharp as this new STM lens on APS-C.
The Canon 24-70/2.8 II is also excellent, but sells for 15 times as much and weighs seven times as much.
There isn't really any comparison. While this lens is simple and inexpensive, it's also optically excellent.
Manual focus is electronic, so there is no manual focus when the camera is off or asleep.
On most cameras, manual focus override only works while the shutter button is held halfway.
It will focus manually when in the MF position whenever the meter is on.
For immediate manual-focus override, you have to be in ONE SHOT AF mode. In AI SERVO mode, most cameras keep trying to change the focus on you, while other cameras simply ignore manual focus in AI SERVO.
In AI FOCUS, the camera selects ONE SHOT or AI SERVO for you depending on if the subject is moving, and if it is and the camera is tracking the subject, it will probably ignore the manual focus ring.
I'd forget the little ES-52 hood. It's an idiotic thing that won't actually shield any light.
Be careful with hoods; if you use a metal screw-in hood you'll rip this plastic lens' guts out if you snag or bang the hood on something.
I had no problems with flare without a hood, so I'd forget it entirely. A hood would triple the size of this thing!
This Canon 24mm f/2.8 STM is an excellent lens for just about anything. You could travel the world for a year and bring back extraordinary images you could publish anywhere, and pull loads of gallery-sized prints for your show.
Ultimately, every shot I make with this little jewel is sharp and clear; it gets focus and makes my shot.
When assembling a system, use this lens to replace an 18-55mm zoom. It's OK to own them both, but never carry them both at the same time.
I use my 24 STM on my 7D Mk II which is a big camera. Having a tiny lens feels great on a big camera, and with a tiny camera like the SL1 will really free you. The less you carry, the more great pictures you'll carry back.
I got mine at Adorama, you also can get them at Amazon and at B&H. If you've found all the time, effort and expense I incur sharing all this information on an ad-free website, my 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.
Canon does not seal its boxes, 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, store demo, damaged, returned or used lens. Buy only from the approved sources I use myself for the best prices, service, return policies and selection.
Thanks for helping me help you!
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28-29 Jan 2015