Introduction

The Canon RF 45mm F1.2 STM is a fast standard prime lens for Canon RF-mount 35mm full-frame mirrorless cameras.

This is a compact and lightweight lens, weighing in at 346g and measuring 78x75mm in diameter and length, yet it still offers a very bright maximum aperture of F1.2 for better low-light performance and bokeh effects.

It slots in above the RF 50mm F1.8 STM and below the RF 50mm F1.4L VCM and the RF 50mm F1.2L USM lenses in the Canon range.

Optically it is comprised of 9 elements in 7 groups and it has a Super Spectra coating on the lens elements to minimize ghosting and flare.

Canon state that this lens offers the same level of image quality as the EF 50mm F1.2L.

Canon’s proprietary STM stepping motor provides smooth, precise and quiet continuous AF while capturing both stills and video.

The minimum focusing distance is 45cm / 17.72" and it has a maximum magnification ratio of 0.13x.

It has a 9 blade aperture which creates an attractive blur to the out-of-focus areas of the image and offers compatibility with Canon’s focus breathing correction technology.

There’s also a configurable lens control ring on the barrel which allows you to quickly change certain key settings including the exposure compensation, shutter speed, aperture and ISO settings.

This lens accepts 67mm filters and there’s a new optional lens hood (ES-73B) available to purchase separately.

The Canon RF 45mm F1.2 STM lens is priced at £479.99 / €549.99 / $469.99 in the UK, Europe and USA respectively. It is available to buy from November 20th 2025. It is made in Malaysia.

Ease of Use

Weighing a mere 346g and measuring 75mm / 2.95 inches in length, the RF 45mm F1.2 STM is one of the more compact lenses that Canon offers in its RF-mount lineup, yet also one of the fastest in terms of its maximum aperture.

It feels very well-balanced on a full-frame camera like the EOS R6 Mark III that we tested it with, providing what is considered by most photographers to be a "normal" field of view.

As you would expect from such an inexpensive lens, build quality is good rather than outstanding. It feels solid enough in your hand despite the all-plastic construction, with the metal mount adding to the solidity.

Note that this lens does not have a weather-resistant design to help protect it against dust and moisture. There is also no optical image stabilizer built-in to this lens.

The fly-by-wire focusing ring is generously sized and it has a rubberised grip band that assists with the operation. There are no hard stops at either ends of the range, making it more difficult to set focus at infinity.

Note that this lens usefully offers full-time manual focusing even when AF is selected. In use the manual focusing system emits an audible "whining" noise that makes it less suitable for video than stills.

When it comes to auto-focusing, the RF 45mm F1.2 STM is a snappy performer thanks to the STM motor, quickly locking onto the subject when mounted on the Canon EOS R6 Mark III camera.

We didn’t experience very much "hunting" at all, either in good or bad light, with the lens accurately focusing virtually all of the time.

The STM motor is also pretty quiet in AF mode, emitting a much quieter "whirr" than when manually focusing, which makes this lens well-suited to auto-focusing during video recording.

The separate Lens Control Ring at the end of the lens barrel can be used to control certain key camera settings (TV, AV, ISO and exposure settings).

Polariser users should be pleased that the sensible 67mm filter thread doesn’t rotate on focus.

There is a petal shaped lens hood (ES-73B) and a soft case available for this lens, but disappointingly both are rather pricey optional extras that aren’t included in the box.

Focal Range

The Canon RF 45mm F1.2 STM’s focal length provides an angle of view of 51° 20.

Chromatic Aberrations

Chromatic aberrations, typically seen as blue or purple fringes along contrasty edges, were not especially apparent in our test shots, only appearing in very high contrast areas.

Vignetting

When shooting JPEGs, with the lens set to its maximum aperture of f/1.2, there is some obvious light fall-off in the corners, requiring you to stop down by at least 2 f-stops to prevent it.

There’s a much larger amount of vignetting evident in the RAW files, though, so make sure to apply the correct lens profile in post-production.

JPEG\

RAW

Distortion

You can’t actually turn off distortion correction in an EOS R camera body when this lens is used - the menu option is actually greyed out and unavailable - which perhaps gives you a good idea of just how much correction the camera is applying!

Still, distortion is well controlled in the resulting JPEG images, so arguably the combination of camera and lens are doing a good job. Again make sure to apply the correct lens profile in post-production for RAW files.

JPEG

RAW

Macro

The Canon RF 45mm F1.2 STM offers a minimum focusing distance of 0.45m / 1.5 feet with a maximum magnification of 0.13x.

Bokeh

Bokeh is a word used for the out-of-focus areas of a photograph, and is usually described in qualitative terms, such as smooth / creamy / harsh etc.

In the RF 45mm F1.2 STM lens, Canon have employed an iris diaphragm with 9 rounded blades, which has resulted in quite nice bokeh in our view for such a wide-angle lens.

We do realise, however, that bokeh evaluation is subjective, so we’ve included lots of examples below for your perusal.

Sharpness

In order to show you how sharp the Canon RF 45mm F1.2 STM lens is, we are providing 100% crops on the following page.

1. Ease of Use
2. 45mm
3. Sample Images
4. Lens Specs
5. Rating & Conclusion
6. Main Rivals
7. Review Roundup