Canon RF 50mm F1.8 STM Review

The Canon SLR system has long included a lightweight, affordable standard base lens. Zeitgeist has applied the Nifty Fifty moniker to the concept, and the RF 50mm F1.8 STM ($ 199.99) is the latest release, this time for Canon’s full-frame mirrorless system. You shouldn’t expect world-class optics, but there’s a lot of appeal for beginners starting with the EOS RP. Professionals shouldn’t give in either. It is not in the same class as the RF 50mm F1.2 L, but it is a good choice for walks, city walks or anytime when you would prefer a thinner kit.

Easy to carry anywhere

The RF 50mm F1.8 is one of the lightest full-frame lenses you’ll find for the system, at just 5.6 ounces. It’s also quite small, coming with 1.6 x 2.7 inches (HD). A thread for 43 mm protective filters and special effects filters is included. Generally speaking, the lens is easier to carry than the large RF 50mm F1.2 L (4.3 x 3.5 inches) and even slightly thinner than the RF 35mm F1.8 Macro (2.5 x 2.9 inches) )).

Top features like weather protection, silent autofocus and stain protection are not included, but we don’t expect them on a $ 200 lens. You get a control ring, one that can be used for manual focusing or as a flexible control ring. An additional lens hood is available as an accessory, but is not included in the box.

The lens barrel includes a toggle switch to change functions, but no switch to switch between autofocus and manual focus. This means that the lens ring will do nothing if it is set as a focus control, and the camera is set to autofocus – you will have to dive into the menu to change the focus mode.

Canon RF 50 mm F1.8 STM

It’s not a bad idea to leave the ring set for focus control most of the time, even if you’re a full-time autofocus photographer, as it can certainly be accidentally rotated, leading to unwanted changes in exposure.

Deliberate adjustment is a pleasant experience – the ring rotates with little resistance and has a slightly dampened response, so you can make minor adjustments without additional worry. This is unlike similar control rings that Nikon includes in its Z series mirrorless lenses that have been hypersensitive to date.

Canon RF 50mm F1.8 STM: Sample image
EOS R5, f / 2.0, 1/8000 seconds, ISO 100

Autofocus is neither instantaneous nor silent. Top lenses focus from the inside, moving only a few elements to lock the focus. The entire RF 50mm optical block moves back and forth to set the focus. This slows down a bit and adds sound to the soundtrack if you are recording a video instead of taking photos.

Will you notice? If you typically use Servo Focus, you’ll feel the lens elements move toward or away from the subject, and the settings aren’t as accurate as any other, which worries about action and burst shooting. For most shots and One Shot focus, however, everything is fine. If the lens needs to be driven across its entire near focus to the far focus range, you can expect a slight lag, at worst about a quarter of a second.

Canon RF 50mm F1.8 STM: Sample image
EOS R5, f / 1.8, 1/1000 second, ISO 100

The manual focusing experience is not bad at all. The answer is accelerating – turn the ring quickly for dramatic focus shifts or slower for less, which is a downside for professional videographers who require repeatable focus stands, but this is not a pro video lens. Focal breathing, an effect that changes the angle of view along with the focus, is visible and another sign on this lens.

It offers a very useful ability to focus up close. Focus is available at just 11.8 inches, measured from the image sensor, good enough for 1: 4 macro magnification in the nearest focus. You can get close to the mid-range RF 35mm F1.8 Macro, a slightly higher quality example that focuses more closely to capture 1: 2 life-size subjects.

Canon RF 50mm F1.8 STM: Sample image
EOS R5, f / 1.8, 1/60 second, ISO 8000

Image stabilization isn’t included in the RF 50mm, so you’ll need to be careful not to work too long at shutter speeds when working with a body that doesn’t have a stabilized sensor – so far it’s only the first generation EOS R and cheap EOS RP. With these bodies, you will want to set the trigger to at least 1/60 second to eliminate blur caused by hand tremors. If you have a calmer hand, 1/30 second is useful.

When paired with a camera with a stabilized image sensor, you will be able to make longer exposures out of your hands. I constantly networked the results without blurring for 1/8 second and I managed to press with a little attention (and occasionally blurry shots) for half a second together with the stabilized EOS R5.

In the lab

I tested the RF 50mm F1.8 STM along with the 45MP EOS R5 and Imatest software. At wider apertures, the lens shows some softness outside the center, but simply slips into our good range of performance in the center (3,000 lines). Nevertheless, you can frame off-center objects and still use the lens wide open and network good-looking images – but you’ll see a little less detail when inserting when printing.

Canon RF 50 mm F1.8 STM

Narrowing the resolution of the f-stop window, not only at the edges, but towards the center. At f / 2.8 you will network slightly better details in the middle, but the edges are raised significantly and will show almost the same contrast as in the center. You’ll get the sharpest photos at f / 4 to f / 8. The results at these apertures are excellent from center to edge, about 4,100 lines.

There is a certain loss of clarity at f / 11 if / 16, but not enough to deter you from using it. You’ll get excellent sun stars with 14 points at f / 16. The aperture can be set to f / 22, but the resolution drops significantly and the sun stars don’t look any better than at f / 16.

Canon RF 50mm F1.8 STM: Sample image
EOS R5, f / 1.8, 1/800 seconds, ISO 100

Corrections in the camera remove almost imperceptible distortions of the tube in the bud. Adobe has not yet added an automatic correction for Lightroom editors, but it’s only a matter of time – we review the lens soon after its release.

See how we test cameras and lenses

The camera also illuminates corners and edges that display a natural vignette from f / 1.8 to f / 2.8. Even with corrections, the images show attenuated angle curvature at f / 1.8 and / 2, but that’s not nearly as dramatic as an uncorrected image.

Bokeh is a great reason to buy shiny, premium lenses. The RF 50mm F1.8 naturally blurs the background, most obviously at lower f-stops. There is no arc ring effect in the focused highlights, but they are not perfectly circular. They take the shape of a cat’s eye towards the edges of the frame at f / 1.8 if / 2. The opening closes into a more circular shape f / 2.8 if / 4. The blur decreases as you further narrow the opening, taking on an octagonal shape by f / 5.6.

Canon RF 50mm F1.8 STM: Sample image
EOS R5, f / 1.8, 1/8000 seconds, ISO 100

I noticed fairly longitudinal chromatic aberrations (LoCA) in the bokeh. It has the shape of green and purple color shifts, which are most noticeable around very bright points of light. If you’re taking a picture on an icy morning or taking macro condensation on the windshield, it’s prominent enough to distract you, but you won’t see it in every picture.

Better than budget

The Canon RF 50mm F1.8 STM is sacrificed to meet its aggressive prices and are mostly understandable. Its autofocus is not the fastest or quietest, but it is better than similar budget items for other systems. It is a very attractive lens for beginners, with a wide aperture for portraits and low light, and the level of construction that we expect from one of the greatest images in painting.

Canon RF 50 mm F1.8 STM

We’d love to see Canon add something between RF 50mm F1.8 and F1.2 L in focal length, although this one is a bit ashamed of what serious hobbyists would want in a lens. If you have a critical eye, this fits well on days when you want to wear a lightweight kit. The RF 35mm F1.8 IS STM is now available for RF photographers who want a premium model with stronger optics priced at around $ 500, and you have the option of using custom SLR lenses with one of Canon’s mount adapters.

For now, we will recommend the RF 50mm F1.8 STM to any Canon owner looking for a lightweight, inexpensive lens. Photographers dipping their fingers into a full-frame pool with an EOS RP should appreciate its price and lightweight workmanship. Shutterbugs and professionals will find that they are a little hesitant about top results and may want to hold out until Canon adds a little more medium in the 50mm focal length, but they have a premium option in the form of an RF-mm of $ 1,300.2 L USM.


  • Autofocus adds sound to the video

  • Visibly focused breathing

  • Not the sharpest at f / 1.8

  • Exposes LoCA in some situations

The bottom line

Canon’s affordable RF 50mm F1.8 STM without mirrors is a good choice for photographers just starting out, but hobbyists may want a little more than an everyday lens.