The EF-s 24 2.8 STM was released Fall 2014 and joins the EF 40 2.8 STM and EF-M 22 2.0 STM as one of three Canon pancake lenses. Here's my thoughts on the EF-s 24 2.8 STM after shooting with it for a couple years.

Koi Ahoy! | EOS SL1 and EF-s 24 2.8 STM | The 24 2.8 STM is a great koi lens!

This review consists of my opinions and observations as a hobbyist. No scientific measurements, MFT charts or pixel peeking comparisons will be found here.

EF-s 24 2.8 STM | Sharp and tiny (image courtesy Canon)

Compatibility

The EF-s 24 2.8 STM lens works on APS-C (1.6X) Canon EOS DSLR cameras such as the Rebel SL3 and 90D. It will also work on EOS R and M series mirrorless cameras with a mount adapter. It does not fit full frame Canon DSLRs and non-Canon cameras such as Pentax, Nikon, Fuji, etc.

Construction

This six-element design is housed in a protrusion barely larger than a body cap, hence the pancake moniker. Mounted on a Rebel SL1, the entire kit slides in my coat pocket and is so light it feels like I forgot the lens! Build quality is great: metal mount, sturdy plastics and attractive industrial satin finish.

EF-s 24 2.8 STM & Rebel SL1 | Fits in a coat pocket or purse

Auto Focus

Auto focus is more sure-footed and peppy than the EF 40 2.8 STM. While AF is generally reliable and accurate, it misses a little more often than my USM primes, e.g., EF 24 2.8 IS USM, mainly when refocusing on the same point in a subsequent photo. The EF 40 2.8 STM is worse in this regard, so Canon may have refined the STM motor's controlling software.

Garden Light | EOS SL1 and EF-s 24 2.8 STM | F10, 1/400 sec, ISO 100

Focus is almost inaudible—a pianissimo "sheeek"—but is picked up by the SL1's built-in mic during quiet video clips. Workarounds include use of an external mic, outboard audio recorders, focusing before shooting or disabling movie servo. However, focus is buttery smooth and ideal for touchscreen pulls during video.

It focuses as near as 6 inches, nipping at the coattails of the macro range. Subject distance is too close to easily illuminate flat art or small products, but I've used it for tight framing of LCD screens and raindrops on windows.

Raindrops on Moonroof | EOS SL1 and EF-s 24 2.8 STM (F2.8)

Manual focus is "focus-by-wire"; i.e., the MF ring isn't mechanically coupled to the lens and is merely a switch for activating focus. Manual focus is smooth and accurate, albeit slow. The nested barrel extends during focus, getting slightly longer at macro distances. It also features FTM (Full-Time Manual), i.e., ability to override AF without flipping a switch. The gotcha is FTM is only active when the shutter button is half depressed.

Image Quality

The slightly wide view coverage of 24mm on APS-C—equivalent in coverage to 38mm on full frame—is ideal for street shooting, landscapes and candids. I love shooting wide open at F2.8 and this lens delivers tack sharp images. Corners are slightly softer but improve when stopped down, equalizing with the center by F4.0.

Light falloff is pronounced at F2.8, nearly two stops below center brightness, but fades by F4. Although light falloff is considered a drawback, the natural vignette is pleasing for portraits and nostalgic landscapes and rarely bothers me.

Symphony Hall | Las Vegas | EOS SL1 and EF-s 24 2.8 STM (F2.8)

Defocused areas at F2.8 have a smooth swirl to them (bokeh), albeit not as pronounced as longer lenses. There is slight chromatic aberration (CA), but only in high contrast light at frame edges, e.g., tree branches against a bright sky.

Canon ES-52 Lens Hood (image courtesy Canon)

Lens Hood

The dedicated hood that fits both the EF 40 2.8 STM and EF-s 24 2.8 STM is the Canon ES-52: basically a 52mm aluminum filter ring around a disk with a hole in the center. It provides almost no shading and protection. If you don't mind spoiling the pancake vibe, a 52mm thread generic metal hood for 28 to 35mm coverage works better.

Gaji Jeans | EOS SL1 & EF-s 24 2.8 STM, F2.8, 1/320, ISO 100

Final Blurb

Normally a Benjamin and a half doesn't buy much in terms of optics but the EF-s 24 2.8 STM lens is an exception: made well, renders beautiful images and is sharp wide open at F2.8. I also own the EF 24 2.8 IS USM and must say, the EF-s 24 2.8 STM, at less than one third the price is just as sharp and vibrant in color clarity. Of course, the more expensive lens also works on full frame cameras, has IS and focuses faster.

Mall Girl | EOS Rebel SL1 and EF-s 24 2.8 STM | F2.8, 1/60, ISO 200

I take the EF-s 24 2.8 STM and my SL1 everywhere and the tiny form factor allows stealth in bars, casinos, restaurants, markets and streets, basically any place where hoisting a big zoom draws unwanted attention. Plus, having it with me all the time often leads to whimsical and off the cuff images. Highly recommended!

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October 2022 Update

I took the EF-s 24 2.8 STM out for a spin on my EOS R7, a Canon APS-C mirrorless camera, and it works great. Of course, an adapter is required but AF is nimble and accurate—better than prior cameras I used it on—and image quality is just as good as it ever was. Of course, the adapter spoils the pancake vibe but it's still a compact unit and the R7 IBIS adds highly effective camera stabilization, improving low light possibilities.

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Specifications

Focal Length: 24mm

Aperture: F2.8 to 22

Lens Construction: 6 elements in 5 groups

Min. Focusing Distance: 0.52 ft./0.16m

Maximum Magnification: .17x

Angle of View (Diagonal): 59°10' (APS-C)

No. of Diaphragm Blades: 7

Filter Size: 52mm

Diameter & Length: 2.7 x 0.9 inch / 68.2 x 22.8mm

Weight: 4.4oz / 125g

Included Accessories: lens caps

Cost: $149.99 (MAP)

EF-s 24 2.8 STM Image Samples | Click to Enlarge

01/06/2015 | Revised 10/31/2023