Canon RF 24-70mm f/2.8L IS USM lens
The RF 24-70mm f/2.8L IS USM delivers superior performance and versatility should make it a ‘must have’ lens for many professionals who use Canon’s EOS R cameras.
Physically and price-wise, this lens is an ideal match for the more solid, weatherproof EOS R camera, although it’s quite comfortable on the less substantial EOS RP, which is large enough to accommodate the professional lens.
Announced in August as part of a trio of L-series f/2.8 lenses for serious photographers, the RF 24-70mm f/2.8L IS USM is the first to be made available for us to review. Covering a ‘standard’ zoom range, this all-purpose lens provides many of the features of the second-generation EF 24-70mm f/2.8L USM for users of Canon’s EOS R mirrorless cameras. But it’s a bit bigger and heavier than the EF mount DSLR lens and considerably pricier, although it’s technically more sophisticated and better suited for shooting video.
Angled view of the RF 24-70mm f/2.8L IS USM lens with the supplied lens hood fitted. (Source: Canon.)
One key difference between the RF lens and its EF equivalent is the inclusion of built-in stabilisation, which claims up to five stops of shake correction. It also has a more complex optical design, with 21 elements in 15 groups, including three aspherical elements plus three elements made from SLD (special low dispersion) glass.
Nine iris blades (one more than in the 12-year-old EF lens) close to a circular aperture to ensure smooth bokeh, while and the RF lens accepts larger 82mm filters. Not surprisingly, the AF drive system is also more sophisticated and uses Canon’s Nano USM technology which combines the fast ring-type ultrasonic motor used in the EF lens with a lead-screw type stepping motor for smooth and quiet focusing during video recording.
Like its EF equivalent, the RF lens boasts a dust- and weather-resistant construction with a fluorine coating on external optical surfaces to repel dirt and grease. This lens is supplied with front and end caps as well as the EW-88E lens hood and LP-1222 soft carrying pouch. It accepts 82 mm diameter filters.
Who’s it for?
Lenses covering a 24-70mm range are sought after for their versatility, being suitable for genres as diverse as portraiture and landscapes and the RF 24-70mm f/2.8 L IS USM is no exception. Event and wedding photographers will find this lens useful for its zoom range as well as its large maximum aperture, which enables good differential focusing with portrait shots, particularly in low light levels.
Dust- and weather-resistant construction plus the grime-resistant coating on external glass surfaces make this lens a good choice for location work. The fast f/2.8 maximum aperture remains constant across the entire zoom range, while the minimum aperture is fixed at f/22.
Capable of focusing at distances from 21 cm (at 24mm) to 38 cm (at 70mm) the RF 24-70mm lens claims ‘reduced’ focus breathing when shooting movie clips. Although quite weighty at 900 grams, it makes an ideal match for the EOS R camera and is well balanced on the lighter EOS RP body we used for our tests.
Build and Ergonomics
The build quality is even better than its EF alternative, which we rated as ‘outstanding’. While not totally waterproof, it is effectively sealed against dust and moisture, making it usable in challenging environments. There’s an obvious rubber flange around the metal mounting plate, which attaches firmly to the camera. The three rings – control, focusing and zoom – move smoothly and feel firm enough to provide precise adjustments.
The 10 mm wide control ring, a characteristic of RF lenses, is located just behind the red ‘signature’ ring that identifies L series lenses, sitting roughly 15 mm aft of the front of the lens when it’s in the 24mm position. It can be assigned to operate functions like aperture and shutter speed settings and its cross-hatched texture makes it easy to identify by touch since the other rings are clad with ribbing.
A 5 mm wide section of the outer barrel separates the control and focusing rings. The focusing ring is approximately 20 mm wide, with most of its surface covered by a finely-ribbed rubber grip band.
It turns through 360 degrees, regardless of whether power is on or off. When the lens is set for manual focusing a distance scale is displayed on the EOS RP’s monitor or EVF screen, depending on which one you’re using. Focused distances aren’t shown in AF mode.
As has become increasingly common, there is no depth-of-field scale and no distance indicator. Neither is essential in a modern camera lens as the former can be viewed or simulated in the EVF and the latter is not sufficiently precise for modern focusing systems. In-camera focusing aids provide much greater precision.
The outer barrel steps in slightly midway through the 6 mm wide fixed section of the barrel between the focusing and zoom rings. Behind it lies the 35 mm wide zoom ring, which is also indented about 10 mm from its trailing edge.
This ring is mostly clad with a thickly-ridged rubber-like substance but ends in a smooth area on which focal length settings for 24mm, 35mm, 50mm and 70mm are stamped. Zooming in from 24mm to 70mm extends the inner barrel by approximately 20 mm, without rotating the front element of the lens.
The wide zoom ring provides excellent control over zooming adjustments. Even though the natural operating position requires finger and thumb for fast zooming, small adjustments are easily made and zooming is very smooth.
Behind the zoom ring lies a 20 mm wide section of the outer barrel that carries slider switches for AF/MF and image stabiliser on/off, which are located around the left hand side and a zoom lock around the right.
We never had to use the zoom lock as the mechanism was firm enough to prevent the lens extending when it was carried pointing downwards. But it’s nice to know it’s there in the remote possibility that the lens could become slacker as it ages.
The outer barrel then steps in to connect with the metal lens mount. The petal-shaped lens hood attaches to a bayonet fitting at the front of the inner barrel and includes a locking button to keep it in place. It’s relatively shallow so it shouldn’t be difficult to adjust angle-critical filters while the hood is in place.
Our shooting tests were carried out with the Canon EOS RP camera, the entry-level model in the current line-up, which has an effective resolution of 26.2 megapixels. As expected for a Canon Nano USM lens, we found autofocusing to be fast, quiet and accurate and the lens was able to fully utilise the tracking capabilities provided by the RP camera. AF lag in movie mode was effectively negligible.
The image stabilisation system worked as well as expected. Canon’s technology is mature so it was no surprise that the claimed five-f-stop advantage proved very credible.
Imatest showed the lens resolution came in just below expectations for the EOS RP’s sensor when JPEGs were analysed. However, our results were consistently above expectations when we analysed CR3.RAW files taken at the same time as the JPEGs. The best performance was at f/4.0 with the 50mm focal length.
Interestingly, high resolution was maintained across all focal length settings from the widest aperture through to about f/11, where diffraction reduced resolution across the board. As an indication of imaging performance, this result is auspicious. Very little edge softening was detected throughout the focal length range, as shown in the graph of our test results below.
Lateral chromatic aberration was consistently negligible at the focal length and aperture ranges, as expected since the camera includes in-built profile corrections for this issue. Interestingly, the raw files we analysed also showed similarly low levels of CA, leading us to conclude this aberration is not problematic. In the graph of our Imatest results below, (which is taken from CR3.RAW files) the red line marks the boundary between ‘negligible’ and ‘low’ CA.
As usual we had to evaluate vignetting and rectilinear distortion by looking at CR3.RAW files, since JPEGs are corrected automatically in the camera. Vignetting was obvious at the widest aperture settings, especially in the corners of the frame, where it could be seen at all focal lengths at f/2.8. Stopping down to f/4.5 eliminated this darkening, again across all focal lengths.
Distortion was relatively low, with slight barrel distortion evident at 24mm. By 35mm no significant distortion could be seen. Slight pincushioning became visible at and 50mm and continued at 70mm. These aberrations can be corrected with editing software.
The review lens didn’t appear to be flare prone in backlit situations, even with wider angles of view. Bokeh was smooth and attractive at all focal lengths although we encountered some circular out-of-focus highlights in close-ups taken at wide apertures.
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Picture angle: 74 degrees to 29 degrees
Minimum aperture: f/22
Lens construction: 21 elements in 15 groups (including 3 aspherical elements plus 3 elements made from SLD glass)
Lens mounts: Canon RF
Diaphragm Blades: 9 (circular aperture)
Focus drive: Nano USM
Stabilisation: Yes, 5 stops
Minimum focus: 21 cm at 24mm, 38 cm at 70mm
Maximum magnification: 0,3x at 32mm
Filter size: 82 mm
Dimensions (Diameter x L): 88.5 x 126.7 mm
Weight: 900 grams
Standard Accessories: Lens front and end caps, EW-88E lens hood, LP-1222 lens pouch
Distributor: Canon Australia; 1800 021 167; www.canon.com.au.
Based upon JPEG files captured by the EOS RP camera
Based on CR3.RAW files recorded at the same time.
Vignetting at 24mm f/4.0.
Vignetting at 35mm f/4.5.
Vignetting at 50mm f/5.0.
Vignetting at 70mm f/5.6.
Rectilinear distortion at 24mm.
Rectilinear distortion at 35mm.
Rectilinear distortion at 50mm.
Rectilinear distortion at 70mm.
24mm focal length, ISO 100, 1/160 second at f/8.
70mm focal length, ISO 100, 1/250 second at f/8.
70mm focal length, ISO 100, 1/1600 second at f/2.8.
Moving subjects; 70mm, ISO 100, 1/400 second at f/8.
Close-up at 24mm focal length, ISO 100, 1/4000 second at f/4.
Close-up at 35mm focal length, ISO 100, 1/160 second at f/2.8.
Close-up at 50mm focal length; ISO 100, 1/4000 second at f/4.
Close-up at 70mm focal length; ISO 100, 1/4000 second at f/4.
Bokeh at 24mm; ISO 100, 1/2500 second at f/2.8. Note the circular highlights in the background near the upper left corner.
50mm focal length, ISO 100, 1/1000 second at f/5.6.
Backlit scene at 24mm focal length, ISO 100, 1/320 second at f/8.
Backlit scene; 41mm focal length, ISO 100, 1/320 second at f/9.
45mm focal length, ISO 100, 1/320 second at f/6.3.
24mm focal length, ISO 12800, 1/13 second at f/8.
26mm focal length, ISO 1000, 1/10 second at f/7.1.
360mm focal length, ISO 100, 1/250 second at f/8.
Crop from the above image enlarged to 100%.
52mm focal length, ISO 4000, 1/40 second at f/8.
24mm focal length, ISO 12800, 1/10 second at f/8.
50mm focal length, ISO 100, 1/250 second at f/7.1.
70mm focal length, ISO 200, 1/500 second at f/6.3.
RRP: AU$4499; US$2299
- Build: 9.0
- Handling: 8.9
- Image quality: 8.9
- Autofocusing: 8.9
- Versatility: 9.0