In summary
Covering the longest zoom range yet for Canon’s EOS R-series cameras, it’s remarkable for the resolution it achieves for its range, size and price.
The 24-240mm zoom range covers most shooting genres, with the wide angle end of the range ideal for landscapes, cityscapes and group portraits, while the 240mm tele end works well for photographing sports and wildlife. Between them lies a range of focal lengths that are ideal for portraiture and general picture-taking.
Note: it’s not weather-resistant so beware of shooting in wet or dusty conditions.
Full review
Announced in February, Canon’s RF 24-240mm f/4-6.3 IS USM lens makes a great partner for the EOS RP, which sits at the entry level to its ‘full frame’ mirrorless camera line-up. Its maximum apertures range from f/4 at the 24mm position to f/6.3 between 109mm and 240mm. Built-in optical stabilisation provides up to five stops of shake correction for both stills and video shooting, with Dynamic IS adding more active video stabilisation when the photographer is moving.
Side view of the RF 24-240mm f/4-6.3 IS USM lens. (Source: Canon.)
The optical design consists of 21 elements in 15 groups and includes one aspherical element and two Ultra-low Dispersion (UD) elements. Super Spectra Coating is applied to minimise ghosting and flare.
Autofocusing is internal and driven by a Nano USM system that utilises both a ring type USM and an STM (stepping motor) mechanism to deliver smooth and near-silent adjustments. Full-time manual focus control is available when working in the one-shot AF mode. It’s compatible with the camera’s Dual Pixel CMOS AF system.
The configurable control ring, which is found on all RF lenses, can be used to adjust exposure settings, including aperture, ISO and exposure compensation. The lens is also equipped with a zoom lock and stabiliser on/off switch as well as a switch for swapping the control ring between manual focus and adjusting the pre-set control.
The maximum aperture range of f/4 to f/6.3 is in line with its other specifications and much as you’d expect from a consumer-level lens. From f/4 at the 24mm position, the maximum aperture declines to f/5.6 at 70mm, closing further to f/6.3 from 109mm to 240mm.
The RF 24-240mm f/4-6.3 IS USM lens weighs a little over 751 grams and is 122 mm long. It will focus to 50 cm at 24mm, extending to 78 cm at 240mm. Although not weather-sealed, it’s both compact and lightweight.
Who’s it For?
This general-purpose lens is ideal for travellers who want a single camera+lens ‘full-frame’ mirrorless kit that can cover most situations they encounter. Weighing roughly 750 grams, it is only 122 mm long at the 24mm position and will focus to 50 cm at 24mm, extending to 78 cm at 240mm.
The all-up weight of this lens plus the EOS RP is 1.235 kg, only 100 grams more than the Olympus OMD E-M1 Mk II plus M.Zuiko digital 12-100mm f/4.0 IS PRO lens. Even though it has a ‘full frame’ sensor, which is four times the size of the M4/3 chip in the Olympus camera, both the Olympus camera and lens are comprehensively weather-sealed and the lens has a constant f/4 maximum aperture throughout its zoom range. Both these features add weight to the combination.
Top view of the RF 24-240mm f/4-6.3 IS USM lens on the EOS RP camera body. (Source: Canon.)
The relatively slow maximum apertures are a direct consequence of the need to keep its size, weight and price as low as possible without unnecessarily compromising optical performance. That Canon has managed this task is to the company’s credit.
The 24-240mm zoom range covers most shooting genres, with the wide angle end of the range ideal for landscapes, cityscapes and group portraits, while the 240mm tele end works well for photographing sports and wildlife. Between them lies a range of focal lengths that are ideal for portraiture and general picture-taking.
Internal focusing, driven by the Nano USM motor is fast and near silent, making it ideal for capturing both stills and video. Full-time focus over-ride enables users to adjust the focus while in AF mode by simply turning the control ring when it’s set to the Focus position.
Five-stop IS allows photographers to shoot with the camera hand-held in low light levels with minimal shake. This lens is also the first Canon has designed for its R-Series cameras to feature Dynamic IS digital stabilisation, which can apply additional correction to counteract shake when recording movies while walking.
Note that this lens is not weather-resistant so don’t take it out for shooting in wet or dusty conditions. If you’re buying this lens for an EOS R or RP camera, check the camera has the latest firmware because both cameras have received firmware updates in the second half of 2019 that include adding support for this lens.
Build and Ergonomics
While not quite a match for Canon’s L-series optics, this lens is nonetheless solidly built with barrels made from polycarbonate. It also has a solid metal mount, both features making it an excellent match for the EOS RP camera on which it was tested.
The two rings feel secure and move easily without containing any slack. The generous zoom ring is located at the front of the outer barrel. It’s almost 65 mm wide and carries a broad (40 mm wide) collar of rubber-like ribbing which is moderately thick and provides an excellent grip.
Zooming requires a rotary motion and going from the 24mm position to 240mm extends two inner barrels, adding approximately 70 mm to the overall length. It’s a smooth motion with no wobbling. The outer barrel carries index marks for the 24mm, 35mm, 50mm, 70mm, 100mm, 150mm and 240mm positions, which are lined up against a white mark on the fixed section of the lens immediately behind the zoom ring.
The control ring is located about 5 mm aft of the zoom ring. It’s 18 mm wide and has a textured surface that looks a bit like cross-hatching but provides a solid grip.
Behind the control ring is a 17 mm wide fixed section of the lens that carries the zoom lock on the right hand side and the Focus/Control and IS switches on the left. The outer barrel slopes inwards to end in the metal lens mount that attaches snugly to the camera body.
Good build quality was confirmed by the fact that we never needed to use the zoom lock when carrying the lens pointing downwards. It’s nice to know it’s there, though, in case some slackness develops over time, although our initial impression is that the lens we received was well built for its type.
The lens is supplied with front and end caps but if you want a lens hood (which we recommend) you’ll have to invest in the optional EW-78F hood (which is listed in Canon’s Australian online store at AU$59.95 but is difficult to find at many online re-sellers). The hood is solidly constructed and includes a locking button to keep it securely in position.
Performance
We tested this lens on the EOS RP body, which confirmed our belief in its suitability for this lens. Our Imatest tests were conducted with all the in-camera corrections in our EOS RP camera enabled (but we also checked a selection of raw files captured simultaneously to identify areas that were potentially problematic).
We were unable to measure performance at the 240mm focal length because of a lack of space in our testing set-up, leaving us with only subjective assessments. For most of the other focal length settings, JPEG files showed slightly higher resolution than would be expected for the 26-megapixel sensor in the review camera; in the best cases expectations were exceeded by a considerable margin.
One thing that surprised us was the consistency of this lens’s performance across its aperture and focal length ranges. The best results came from a stop or two down from the maximum apertures for the 35mm, 50mm and 70mm focal lengths but high resolutions persisted through a wide range of aperture settings, right up to f/11, where diffraction began to take effect, as shown in the graph below.
By 100mm we noticed a slight loss of central sharpness when files were examined closely and this became more obvious at 200mm. Both were confirmed in our Imatest tests. Edge softening was less than expected for a lens of this type but present at all focal lengths, decreasing gradually as the aperture was stopped down.
The raw files we measured turned in resolutions that ranged from slightly above their equivalent JPEGs to substantially higher. But they also showed up any inherent lens aberrations which fortunately, were mostly corrected by the EOS RP’s JPEG processing.
Also corrected in the camera was lateral chromatic aberration (which is also easily corrected when raw files are converted into editable formats). The graph below shows lateral chromatic aberration remained well within the lower portion of the ‘negligible’ band for all focal length and aperture settings. (The red line marks the border between ‘negligible’ and ‘low’ CA.)
Because of the effectiveness of the in-camera corrections we found no obvious evidence of coloured fringing along high-contrast boundaries in JPEG images. However, when we examined raw files recorded simultaneously, both purple and green fringing were obvious. Examples are provided below.
The original image, 240mm focal length, ISO 400, 1/320 second at f/9.
Crops from the centre of the frame (where the lens was focused) show the differences in sharpness between the JPEG file (top) and the CR3.RAW file (below it), which was recorded simultaneously and converted into 16-bit TIFF format with Adobe Camera Raw.
Crops at 100% magnification taken from the upper left corner of the frames, again with the JPEG file upper and the converted raw file below. Note the purple and green fringes along the contrast boundaries in the raw file crop. Chromatic aberration has been almost completely corrected in the JPEG file (although both files remain relatively unsharp due to a loss of resolution at the edges of the lens field of view).
Crops at 100% magnification taken from the middle right side of the frames, again with the JPEG file upper and the converted raw file below, confirming the correction of the chromatic aberration in the camera – and also the inherent edge softening in the lens.
Because both vignetting and rectilinear distortion are automatically corrected by the camera’s JPEG processing, based upon pre-loaded lens profiles, we had to assess these potential problems by looking at uncorrected raw files. Selecting the lens profile in Adobe Camera Raw enabled us to remove aberration almost completely, although we had to apply additional correction via the slider provided on the profile page.
Vignetting was obvious in uncorrected raw files, particularly at the 24mm focal length, where there was strong corner darkening. With all the other focal lengths, vignetting was less severe, with the least obvious darkening at the 35mm focal length.
It’s common to see rectilinear distortion in kit zoom lenses so some degree of distortion was expected in uncorrected files. While severe barrel distortion was seen in uncorrected raw files at 24mm, it was relatively low by 35mm and 50mm, after which it segued into increasingly obvious pincushion distortion as the lens was zoomed in.
Interestingly, the review lens was very resistant to both ghosting and flare, although we managed to produce a couple of tiny flare artefacts at the 24mm position when a bright light source was included within the frame. Veiling flare was not generated and normally backlit shots showed no loss of contrast. Unlike the other aberrations, flare isn’t corrected automatically in the camera, so this is a significant tick in the lens’s favour.
Autofocusing was something of a mixed bag. While the lens focused quickly and accurately on the EOS RP camera at focal lengths up to about 130mm, going from grossly out-of-focus to pin sharp in less than half a second, from 150mm on, it often seemed unable to focus.
This didn’t happen all the time but was common enough to be annoying. Fortunately, zooming back to about 100mm and re-focusing with the AF system appeared to re-set focusing and it was then both quick and easy to focus at the extremities of the zoom range. While it’s a mild irritation when shooting static subjects, this issue can be problematic if you’re trying to shoot sports or wildlife action.
It’s likely to be caused by the lack of lens speed at longer focal lengths; f/6.3, which is the maximum aperture at 150mm and 240mm isn’t letting a lot of light into the camera for the AF system to work with. And this loss of light doesn’t show up in the camera’s EVF or on the monitor screen.
Bokeh at the widest apertures was generally quite pleasing. Defocused areas appeared smooth, particularly at longer focal lengths; although they were smoother than expected at 24mm and we found no outlining around bright highlights.
Conclusion
Please Login or Register to access the Conclusion.
SPECS
Picture angle: 74 degrees to 8 degrees 35 minutes
Minimum aperture: f/22-f/38
Lens construction: 21 elements in 15groups (including 1 aspherical and 2 UD elements)
Lens mounts: Canon RF
Diaphragm Blades: 7 (circular aperture)
Focus drive: Nano USM
Stabilisation: Built-in, 5 stops of shake correction
Minimum focus: 50 cm
Maximum magnification: 0.26x
Filter size: 72 mm
Dimensions (Diameter x L): 80.4 x 122.5 mm
Weight: 750 grams
Standard Accessories: Lens front and end caps, lens hood,
Distributor: Canon Australia; 1800 021 167
TESTS
Based on JPEG files taken with the EOS RP camera.
Based on CR3.RAW files converted into 16-bit TIFF format with Adobe Camera Raw.
SAMPLES
Vignetting at 24mm f/4.0. CR3.RAW file.
Vignetting at 35mm f/4.5. CR3.RAW file.
Vignetting at 50mm f/5.0. CR3.RAW file.
Vignetting at 70mm f/5.6. CR3.RAW file.
Vignetting at 100mm f/5.6. CR3.RAW file.
Vignetting at 150mm f/6.3. CR3.RAW file.
Vignetting at 240mm f/6.3. CR3.RAW file.
Rectilinear distortion at 24mm. CR3.RAW file.
Rectilinear distortion at 35mm. CR3.RAW file.
Rectilinear distortion at 50mm. CR3.RAW file.
Rectilinear distortion at 70mm. CR3.RAW file.
Rectilinear distortion at 100mm. CR3.RAW file.
Rectilinear distortion at 150mm. CR3.RAW file.
Rectilinear distortion at 240mm. CR3.RAW file.
24mm focal length, ISO 100, 1/500 second at f/8.
35mm focal length, ISO 100, 1/640 second at f/8.
50mm focal length, ISO 100, 1/640 second at f/8.
70mm focal length, ISO 100, 1/500 second at f/8.
100mm focal length, ISO 100, 1/400 second at f/8.
150mm focal length, ISO 100, 1/400 second at f/8.
200mm focal length, ISO 100, 1/320 second at f/8.
Close-up at 24mm focal length, ISO 100, 1/400 second at f/4.
Close-up at 240mm focal length, ISO 160, 1/320 second at f/6.3.
Close-up at 240mm focal length showing smooth bokeh; ISO 160, 1/320 second at f/6.3.
Absence of flare at 24mm focal length, ISO 100, 1/800 second at f/8.
Very strong backlighting at 24mm focal length, ISO 100, 1/1000 second at f/8.
24mm focal length, ISO 100, 1/400 second at f/8.
55mm, ISO 100, 1/125 second at f/8.
240mm focal length, ISO 320, 1/320 second at f/6.3.
240mm focal length, ISO 100, 1/640 second at f/7.1. From CR3.RAW file.
Crop from the above image enlarged to 100% showing coloured fringing.
Close-up in tricky lighting; 240mm focal length, ISO 640, 1/250 second at f/7.1.
240mm focal length, ISO 100, 1/800 second at f/6.3.
178mm focal length, ISO 100, 1/320 second at f/6.3.
Moving subject(s);240mm focal length, ISO 125, 1/250 second at f/6.3.
240mm focal length, ISO 125, 1/250 second at f/8.
58mm focal length, ISO 100, 1/400 second at f/9.
24mm focal length, ISO 100, 1/400 second at f/9.
35mm focal length, ISO 500, 1/60 second at f/4.5.
140mm focal length, ISO 100, 1/320 second at f/9.
130mm focal length, ISO 100, 1/200 second at f/6.3.
165mm focal length, ISO 100, 1/200 second at f/7.1.
40mm focal length, ISO 250, 1/80 second at f/9.
Photographed through glass; 94mm focal length, ISO 125, 1/100 second at f/6.3.
90mm focal length, ISO 3200, 1/100 second at f/8.
Rating
RRP: AU$1393.21; US$900
- Build: 8.8
- Handling: 8.9
- Image quality: 8.8
- Autofocusing: 8.3
- Versatility: 9.0
BUY