A full-frame F1.2 lens is supposed to be absurdly expensive, but Canon clearly missed that memo. Its RF 45mm F1.2 STM ($469.99) is the first extra-bright prime from a major brand to enjoy triple-digit pricing; it's a steal when compared with the RF 50mm F1.2 L USM ($2,599). The 45mm F1.2 doesn't focus as quickly and exhibits some false color that its premium L-series cousin avoids, but photographers who want to try their hand at creating photos with an extremely shallow depth of field can choose to overlook some technical flaws, given just how affordable the 45mm F1.2 is. It's about double the price of Canon's least expensive standard angle prime, the RF 50mm F1.8 STM ($239), but its exotic F1.2 optics gather more light for greater background blur, making the RF 45mm stand out far enough from the pack to earn our Editors' Choice award.

Design: Excellent Light Gathering From a Featherweight Lens

The 45mm F1.2 is one of the smallest, lightest autofocusing F1.2 primes for any full-frame system. It measures a mere 3.0 by 3.1 inches (HD), weighs 12.2 ounces, and is compatible with 67mm filters. It's a featherweight when compared with the RF 50mm F1.2 L USM (4.3 by 3.5 inches, 2.1 pounds, 77mm filters), though to be fair, the 50mm F1.2 qualifies as a large prime. The RF 50mm F1.8 STM (1.6 by 2.7 inches, 5.6 ounces, 43mm filters) is the smallest wide-aperture prime for the system; when used at maximum aperture, it captures about half as much light as an F1.2 lens, but is the one to get for light carry.

(Credit: Jim Fisher)

As for how Canon managed to squeeze F1.2 optics into a relatively tiny lens, there are two major factors. Its optical formula is the first: The 9-element/7-group arrangement is mostly optical glass, but has one plastic molded (PMo) aspherical element that cuts weight (and production cost) versus aspherical glass. Secondly, the lens relies on digital corrections to remove some distortion and compensate for a vignette, so the optics don't have to do all the lifting. Canon leverages a similar design philosophy for another one of my favorite budget lenses for the system, the RF 28mm F2.8 STM pancake prime.

(Credit: Jim Fisher)

Canon leans into minimalist aesthetics for the RF 45mm (and most of its other RF lenses, for that matter). The polycarbonate barrel is matte black, with minimal flair, featuring a silver embossed Canon logo and the number 45 printed below it in white. The lens ships with front and rear caps, but does not include a hood. Canon's ES-73B accessory hood is sold separately for $59. At press time, no third-party hoods are available to fit the RF 45mm's front bayonet mount, although I expect that to change over time. Wait a few months, and you'll likely be able to find a cheap hood.

(Credit: Jim Fisher)

In what's likely a cost-saving move, Canon decided to skip weather sealing for this lens. I feel comfortable using it in light precipitation, but would caution against using it on a day when you feel compelled to use an umbrella. Likewise, the front glass does not include the anti-smudge fluorine protective coating that many professional lenses have, which means you'll need to use a lens wipe to remove an accidental fingerprint, and drops of water will leave a mark. Thankfully, the front glass is relatively small and recessed into the barrel, so the chances of getting it dirty are minimized.

Controls and Focus: Sluggish Performance Is Part of the Price

The RF 45mm F1.2 STM includes two rings: one for manual focus and a configurable control ring that adjusts either aperture, EV compensation, or ISO; the specific function is set via the camera menu. The control ring clicks as it turns, adjusting exposure by a third of a stop with each click. If you prefer a smooth, continuous action, you can have Canon's service department make the change for $79.99.

(Credit: Jim Fisher)

There's also an AF/MF toggle switch on the barrel, allowing you to easily switch between focus modes. Manual focus is linear, meaning the focus shifts based on the ring's angle of rotation, regardless of the speed. Thankfully, the focus throw is decently long, it's about 200 degrees between the shortest focus distance and infinity.

(Credit: Jim Fisher)

Autofocus is on the slow side. It takes approximately 0.7 seconds for the lens to shift from a far-off to a close focus distance with the EOS R5 Mark II. The lens is also slightly noisy when focusing. It's loud enough that you can hear the whir of its motor in a quiet room, and the camera's mic picks up the noise when recording video, too. This comes from the focus motor, a gear-type STM that helps to keep the lens cost down, but isn't as speedy or quiet when compared with the voice coil motor in lenses like the RF 50mm F1.4 L VCM ($1,549) or the ultrasonic motor in the RF 50mm F1.2 L USM.

(Credit: Jim Fisher)

The RF 45mm F1.2 is a so-so option for macro photos. It focuses as close as 17.7 inches (45 centimeters), which nets a maximum 1:7.7 reproduction ratio. I took the lens to a botanical garden for some photos and found that it's good enough for close-ups of larger flowers, but I missed capturing the tiny details that a proper macro lens, such as the RF 35mm F1.8 Macro IS STM, can bring into view.

(Credit: Jim Fisher)

Image Quality: Strong Detail and Characterful Bokeh

I used the RF 45mm F1.2 STM with two different cameras. I took most of my sample images with the EOS R6 Mark III, and ran Imatest labs with the 45MP EOS R5 Mark II. The RF 45mm delivers good central detail at its maximum aperture (3,100 lines) and captures sharper detail at narrower apertures. At f/1.4 it ticks up slightly (3,400 lines), and takes a leap to excellent at f/2 (4,000 lines), f/2.8 (4,100 lines), and f/4-5.6 (4,900 lines). Edges aren't as crisp as the center at any aperture, but are good enough for landscapes in the f/4-11 range (2,700-3,000 line). I don't count the soft edges as a problem; at wide f-stops, edges are naturally blurred by bokeh, and the RF 45mm is sharp enough across the frame when stopped down.

(Credit: Jim Fisher)

As mentioned, the lens relies on digital corrections to remove distortion and compensate for a vignette. If you use your camera for JPGs, HEIFs, or video, the profile is applied automatically and transparently. If you opt for Raw capture instead, you'll want to apply a lens correction profile, as photos show noticeable barrel distortion and darkened corners without one. The most recent releases of Adobe Lightroom and Lightroom Classic support the lens. However, if you use a different workflow app, it's worth verifying that it also supports the RF 45mm.

(Credit: Jim Fisher)

I'm quite impressed with how well the RF 45mm F1.2 controls flare, which can be a real problem with extra-bright lenses. I made several images directly into the sun and see no noticeable drop in clarity. I am able to induce false color if the light hits the lens at the right angle—you can spot a purple orb in the preceding image—but a slight shift in angle is enough to minimize the effect. Reflections are more prominent at narrower apertures, so it's also worthwhile to try opening the iris if you want to avoid the effect. On the other hand, you can use a narrow aperture to create a sunstar effect in bright points of light, but doing so will exacerbate any ghosting. Therefore, adjust the camera angle to minimize this effect. The following image represents a worst-case scenario for reflections.

(Credit: Jim Fisher)

The RF 45mm F1.2's biggest strength is its bright, background-blurring aperture. The lens catches just a tiny sliver of the world in focus when used wide open. The blur itself has a busy character, a look that some photographers embrace but may turn off those who prefer smoother bokeh. I see purple and green false color (a type of longitudinal chromatic aberration) and double-edged highlights with a cat's-eye shape, both of which add texture to the background. On a positive note, the PMo lens element avoids the onion-skin highlight texture that glass aspherical elements typically create.

(Credit: Jim Fisher)

Backgrounds take on more definition at narrower apertures, but the lens also shows less LoCA, and highlights take on a uniformly round shape in the f/2-4 range. If you're looking to get cleaner bokeh from the lens, it's not a bad idea to ratchet the aperture down to f/2; you'll still get plenty of blur (especially when you're focusing near the lens's minimum working distance). This gives the RF 45mm F1.2 a leg up in flexibility versus the RF 50mm F1.8, which also shows some false color wide open, but requires you to stop down to f/2.8 to minimize the effect.

(Credit: Jim Fisher)