Canon RF 28mm F2.8 STM

The Canon RF 28mm F2.8 STM ($299.99) is a fine example of one of the most beloved concepts in photography: the pancake lens. There's no maple syrup involved, of course, just a slim, lightweight optic that works well with both full-frame and crop-sensor cameras. The moderately wide-angle RF 28mm snaps sharp photos, has fast enough optics to capture soft backgrounds, and comes in at an attractive price for both photo enthusiasts and beginners who want to try a prime lens. All those qualities make the RF 28mm an Editors' Choice winner and an easy recommendation for most Canon photographers.

So, So Small

Although the RF 28mm's tiny frame is far from its only compelling feature, it is the most obvious characteristic. It's not an unheard of concept—Canon had a couple of slim primes in its SLR lens catalog, and rival Nikon sells the similar Nikkor Z 26mm F2.8—but pancake lenses aren't the norm.

At just 1.0 by 2.7 inches (HD) and 4.2 ounces, the lens doesn't add much volume or weight to your camera. Despite its size, it works with full-frame cameras like the EOS R6 Mark II to capture a view that's just a little narrower than the RF 24-105mm F4-7.1 IS STM zoom at its widest. It pairs well with crop-sensor cameras too, including the tiny EOS R100 and the mid-sized EOS R7. I especially like using the 28mm with the R100, since the combination easily slides into a coat pocket or small bag.

On a full-frame camera, the 28mm angle is best for portraits that include some of the world around your subject, group photos, landscapes, and street photography. It's a similar use case to your smartphone's main lens. The 45mm equivalent angle on crop-sensor cameras makes it easier to isolate subjects and induce background blur. It's still a standard focal length though, so it's not suitable for far-off subjects. In testing, the lens worked well for capturing a lounging cat on a street corner and glimmering rocks in a nearby stream.

Canon doesn't include a lens hood, but it does sell an overpriced add-on for $45. I wouldn't bother with it, since the exposed front element is small enough to minimize off-angle light by itself. If you want to protect the front element, consider adding a multicoated 55mm filter. The lens is not weather-sealed, but it does include a metal bayonet mount rather than a plastic one like some other low-cost entries such as the Canon RF 24-50mm zoom.

Just one other prime lens in Canon's library has a similar focal length, the RF 24mm F1.8 Macro IS STM ($499). It's a bit larger, but still relatively compact at 2.9 by 2.5 inches, and 9.5 ounces. I haven't tested it yet, but its technical advantages are pretty clear: It can blur backgrounds more readily thanks to its brighter aperture and macro capabilities, and includes optical stabilization (which is missing from the RF 28mm). Third-party alternatives are nonexistent. Canon doesn't let others make autofocus lenses for RF at this time, so off-brand options are limited to manual-focus, cinema, and other special-use glass.

Is There Any Room for Control?

Bigger lenses typically pack lots of buttons, toggle switches, and control rings, but there's no room for all that on the RF 28mm's 1-inch barrel. That said, it does offer a multifunction control ring and a toggle switch to set its behavior between Autofocus (AF), Control, and Manual Focus (MF) modes. The ring does nothing in AF mode, changes the ISO, EV value, or another custom setting in Control mode, and sets focus in MF mode.

The Control ring is narrow, but still easy enough to find by touch thanks to its position at the front of the barrel and diamond-knurled texture. It turns with a pleasing amount of resistance, thus giving you precise control over aperture, EV, or whatever function you assign it.

I like the manual focus experience. The ring's dampened feel is a benefit, while the nonlinear response makes it easy to shift focus dramatically with a quick twist or more deliberately with a slow turn.

Although the nonlinear response is an advantage for locking in focus for still photos, it's less desirable for serious video work. A linear response is better for the latter because it lets a camera operator repeat the same focus shift across multiple takes of a scene. I don't think any Hollywood Directors of Photography (DPs) or indie filmmakers will pick this lens, though, because it shows a huge amount of focus breathing. The lens shifts its entire optical group to set focus and makes no effort to correct for changes in the angle of view. At close focus distances, the lens shows a noticeably narrower frame than at infinity.

I tested the autofocus speed with the snappiest full-frame camera I had on hand, the EOS R6 Mark II. The camera's tracking system quickly locks onto subjects and the lens does a fine job of keeping them in focus if they are moving toward or away from the camera. You might notice a delay when you move from a near subject to a far one or vice versa, however, since the lens takes a split second to drive its focus across the range. Lenses that use internal focus elements are universally faster, but I don't consider the slower response a practical limitation of the 28mm given its wide angle of view.

The lens focuses to 9.1 inches for a meager 1:5.8 macro rating. It's good enough to get decent close-ups of traditional macro subjects like flowers, but you won't be able to hone in on small details like you can with a true macro lens. The RF 24mm F1.8 IS STM Macro and RF 35mm F1.8 IS STM Macro both focus closer for half-size (1:2) magnification.

Canon leaves off optical stabilization for the lens, something to remember if your camera also lacks the feature. The EOS R7, R6, R5, and R3 series all have in-body image stabilization (IBIS), but more affordable options like the R8, RP, R10, R50, and R100 don't. Keep your shutter speed at 1/30-second or shorter to get sharp results without the benefit of IBIS. With a stabilized camera, I got crisp handheld results at up to 1/2-second.

Canon RF 28mm STM: In the Lab

I used the RF 28mm with a few different cameras out in the real world, but I reached for Canon's highest-resolution full-frame body, the 45MP EOS R5, for lab tests. The lens delivers very good contrast (3,900 lines) for the 45MP chip at f/2.8 and crosses over to the excellent range at f/4-f/8 (4,100-4,300 lines).

Photos are a little softer at f/11 due to diffraction (3,700 lines), but still in the very good range for the R5. Images show less detail at f/16 (3,100 lines) and f/22 (2,300 lines). You can get sun stars at these settings, but they look only average, with long tines that spread out into streaks. If you're looking for crisp, pointy sunstars, the RF 15-35mm F2.8 L IS USM is (pardon the pun) a stellar, but expensive alternative.

Like nearly every made-for-mirrorless lens, the RF 28mm F2.8 STM relies on digital correction to compensate for barrel distortion and a natural vignette. If you set your camera to snap JPGs, you won't ever notice the issue as both pictures and the preview in the viewfinder are corrected. And if you use the Raw format, photo editing software like Adobe Lightroom and Capture One includes a correction profile. Just note that turning off distortion correction for photos without distracting barrel distortion gets you a slightly wider angle of view.

The somewhat wide angle of view from the lens means you won't see bokeh in every picture, but it's still capable of softening backgrounds in the right situations. Defocused highlights look busier than from an F1.8 optic for sure, but they show generally soft edges and no signs of the ugly onion skin effect. The lens does a fine job of suppressing false color (LoCa) in backgrounds.

An Affordable, Sharp, and Small Prime

The RF 28mm F2.8 STM is a little gem of a lens. Its small size makes it enjoyable to carry around, while its moderately wide angle is suitable for walks around town, environmental portraits, and snapshots. Simply put, its price, performance, and pancake design make it special enough to warrant our Editors' Choice award. If you need a slightly more premium optic, the RF 24mm F1.8 Macro IS STM is close in focal length and seems like a worthwhile value given its brighter aperture, macro capabilities, and optical stabilization, though it's not nearly as compact as the 28mm.