Canon RF 24-50mm f/4.5-6.3 IS STM lens

      Photo Review 8.6

      In summary

      The RF 24-50mm f/4.5-6.3 IS STM lens represents quite good value for money in the light of its measured performance. It’s also a reasonable choice when light weight and compact size are high priorities – provided you can work with the focal length limitations.

      We wouldn’t go out of our way to purchase this lens since there are other, more versatile, options available.  The RF 24-105mm f/4-7.1 IS STM lens is only a little more costly but heaps more versatile, while the RF 24-240mm f/4-6.3 IS USM lens would provide a better, all-in-one choice for travellers and those who enjoy shooting sports and wildlife.

      Full review

      Canon’s RF 24-50mm f/4.5-6.3 IS STM lens was announced on 8 February concurrently with the EOS R8 and R50 cameras and the RF-S55-210mm f/5-7.1 IS STM telephoto kit lens for the R50. An entry-level product, it will be offered as a kit lens with the R8 camera, which was used for this review and is reviewed separately, the 24-50mm provides an affordably-priced lightweight lens for everyday photography. It will be available separately for an RRP of AU$549.

      Angled view of the RF 24-50mm F4.5-6.3 IS STM lens without end caps. (Source: Canon.)

      The RF 24-50mm F4.5-6.3 IS STM lens is relatively slow and has a short (just over 2x) zoom range but includes in-lens optical stabilisation. Like many kit lenses it has a plastic mount and features a retractable design. It comes with the standard front and end caps but the EW-63C lens hood is an optional extra.

      Who’s it For?
      Photographers looking for a compact, lightweight and inexpensive general-purpose lens for their full-frame Canon mirrorless cameras are the main target market for this lens – but we don’t think many will purchase it as a stand-alone unit.  While it’s reasonably priced part of a bundle, this lens simply isn’t versatile enough to choose on its own.

      Not only is it slow, but it only offers a 2x zoom range. Physically, it would be out of place on more sophisticated, weather-resistant bodies like the EOS R6 II and its overall performance is not good enough for the 45-megapixel EOS R5.

      That said, the light weight wouldn’t be out of place on cropped-sensor models like the EOS R50 and EOS R10, where the 80mm equivalent focal length at the 50mm position would be good for portraiture.   But landscape and cityscape photographers would be short-changed by the 38.4mm equivalent focal length at the wide end of the zoom range.

      At a pinch, this lens could be justified as an emergency backup for larger and faster lenses with similar focal lengths when the photographer’s kit weight needs to be kept low. However, the relatively slow maximum aperture at this setting doesn’t provide much scope for selective focusing, although the quiet STM autofocusing system is great for videography, including documenting family activities.

      Build and Ergonomics
      As is usual for a kit lens, the RF 24-50mm f/4.5-6.3 IS STM lens is made mainly from plastic. Although it is only 58 mm long when retracted, the inner barrel extends by approximately 30 mm, taking the overall length to roughly 88 mm at the 24mm shooting position.

      This illustration shows the lens in the extended and retracted positions. (Source: Canon.)

      Zooming to 50mm turns the ring through approximately 55 degrees and pulls it back by approximately 8 mm.  The shortest overall length is at around the 42mm focal length position.

      The textured Control Ring, which defaults as a manual focusing ring, is located at the leading edge of the outer barrel. This ring can be rotated through approximately 220 degrees to provide a fair amount of control over adjustments.

      It’s roughly 10 mm wide and can be configured to adjust settings such as aperture, ISO and exposure compensation (which over-ride manual focusing). Move the Focus/Control switch to the MF position to prioritise manual focus.

      The zoom ring lies just behind the Control Ring. It’s 17 mm wide and has a band of widely-spaced ribbing covering most of its surface, with an un-ribbed band behind it that carries the focal length markings for the 24mm, 28mm, 35mm and 50mm positions, which are aligned against a mark on the fixed section of the barrel behind.

      The maximum and minimum apertures change as the focal length is increased as shown in the table below.

      Focal length 24mm 28mm 35mm 50mm
      Maximum aperture f/4.5 f/5.0 f/5.6 f/6.3
      Minimum aperture f/22 f/25 f/29 f/32

      If you switch the camera on with the lens retracted, it will display the following message: Set the lens to the shooting position. You need a firm twist of the zoom ring to over-ride the click-stop and unlock the retracted lens before it can be used and a reverse twist to pack it away for storage. No distance scale is provided.

      The 24 mm wide section of the outer barrel between the zoom ring and the lens mount carries two slider switches: The upper one is for switching between AF, Control and MF positions, while the lower one turns the image stabiliser on and off.

      There’s a red index mark on the gunmetal-coloured band around the lens mount to provide guidance when fitting the lens to a camera. Twelve gold-plated contacts sit inside the plastic mount for passing data between the camera and the lens.

      Despite not being weather resistant, the review lens fitted quite snugly to the EOS R8 camera body we used for this review. However, it’s worth noting the lack of weather sealing and the front and rear elements are not fluorine-coated to repel dust and moisture, so careful handling will be required.

      Our Imatest tests showed the review lens to be competent for its type, with measured resolution in the centre of the frame in JPEG files exceeding expectations at the 24mm focal length with an aperture of f/6.3. CR3.RAW files recorded simultaneously produced resolutions well in excess of expectations for the review camera’s 24-megapixel sensor.

      As anticipated, resolution was lower towards the edges of the frame for both JPEG and raw files, although not quite as much as we had expected. The graph below shows the results of our tests for JPEG files across the main focal length and aperture settings.

      Lateral chromatic aberration measurements fell well within the ‘negligible’ band, even when based on CR3.RAW files with optical corrections disabled in Adobe Camera Raw. In the graph of our test results below, the vertical red line marks the boundary between ‘negligible’ and ‘low’ CA.

      Interestingly, we found evidence of coloured fringing in high-contrast areas of some raw files when they were converted into editable formats. The illustration below shows an example of the reddish fringing on the left and the same image after manually corrections with the defringing tool in Adobe Camera Raw.

      Coloured fringing (red) along contrasty areas in the uncorrected raw file (left) and after defringing adjustments (right) in Adobe Camera Raw.

      JPEG file from the above pair for comparison; 24mm focal length, ISO 800, 1/80 second at f/10.

      Like chromatic aberration, vignetting and rectilinear distortion had to be assessed through raw files with all optical and profile corrections disabled in Adobe Camera Raw. Both were quite extreme at the wider angles of view, but reduced as the focal length was increased, although some evidence of both aberrations remained at 50mm. Fortunately, they are effectively addressed with automatic in-camera correction for JPEGs and adjustments most raw file converters.

      Test shots showed the review lens to be susceptible to both veiling flare and flare artefacts when a bright light source was inside the image frame. This isn’t surprising since it is supplied without a lens hood. When the sun was outside the frame, flare was negligible and we found very little loss of contrast and colour saturation in the shots we took, especially with raw files.

      The seven-bladed iris diaphragm produced 14-pointed sunstars when the lens was stopped down to its minimum aperture. However, the resulting images were softened a little as a result of diffraction and the wide angles of view meant they were relatively small within the frame.

      Bokeh was much as we expected from an ultra-wide, relatively slow short zoom lens since it’s difficult to blur the background satisfactorily at the minimum focus distance with wide angle of view. But few photographers would consider using this lens for close-ups with a shallow depth of field when better alternatives exist.

      Autofocusing was generally fast and accurate with most types of subjects in different lighting conditions and able to adjust quickly as conditions changed. It was also very quiet, thanks to the stepping motor drive. Focus breathing was detected at a relatively modest level.

      Although stabilisation is seldom needed in ultra-wide angle lenses, this lens benefits from its built-in OIS. We found few instances of camera shake affecting our test shots and those were mostly due to careless shot framing with the camera set in the P mode.


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      Picture angle: 84 to 46 degrees (diagonal)
      Minimum aperture:  f/22-f/32
      Lens construction: 8 elements in 8 groups (includes one ED and 2 aspherical elements plus Canon Super Spectra coating)
      Lens mounts: Canon RF
      Diaphragm Blades: 7 (rounded aperture)
      Weather resistance: No
      Focus drive: Leadscrew-type stepping motor (STM) with internal focusing
      Stabilisation: Yes; 4.5 stops shake correction (up to 7 stops with co-ordinated in-camera IS)
      Minimum focus: 30 cm at 24mm; 35mm at 50mm
      Maximum magnification: 0.11x at 50mm
      Filter size: 58 mm
      Dimensions (Diameter x L): 69.6 x 58 mm  (retracted)
      Weight: 210 grams
      Standard Accessories: Front and end caps

      Distributor: Canon Australia; 1800 021 167



      Based on JPEG files taken with the Canon EOS R8 camera.

      Based on CR3.RAW files converted into 16-bit TIFF format with Adobe Camera Raw.



      Vignetting at 24mm, f/4.5.

      Vignetting at 28mm, f/5.0.

      Vignetting at 35mm, f/5.6.

      Vignetting at 50mm, f/6.3.

      Rectilinear distortion at 24mm.

      Rectilinear distortion at 28mm.

      Rectilinear distortion at 35mm.

      Rectilinear distortion at 50mm.

      24mm focal length, ISO 100, 1/60 second at f/8.

      50mm focal length, ISO 160, 1/60 second at f/8.

      Crop from the above image magnified to 100% showing coloured fringing.

      Close-up at 24mm focal length, f/4.5, ISO 100, 1/125 second.

      Close-up at 50mm focal length, f/6.3, ISO 250, 1/80 second.

      Sunstar in close-up at 24mm focal length, f/22, ISO 1000, 1/60 second.

      Sunstar and flare artefacts in close-up at 50mm focal length, f/32, ISO 1600, 1/60 second.

      Sunstar at 24mm focal length, ISO 400, 1/60 second at f/22.

      Sunstar and flare artefacts at 50mm focal length, ISO 400, 1/50 second at f/32.

      Flare; 50mm focal length, ISO 1600, 1/25 second at f/22.

      Close-up at 50mm focal length, f/7.1, ISO 2000, 1/60 second.

      24mm focal length, ISO 1000, 1/80 second at f/11.

      14mm focal length;
      ISO 200, 1/60 second at f/10.

      41mm focal length, ISO 200, 1/80 second at f/6.3.

      24mm focal length; ISO 125, 1/60 second at f/4.5.

      220: 50mm focal length, ISO 200, 1/60 second at f/6.3.

      Additional image samples can be found with our review of the EOS R8 camera.



      RRP: AU$549

      • Build: 8.9
      • Handling: 8.9
      • Image quality: 9.0
      • Autofocusing: 8.9
      • Versatility: 8.3