First test
ON TEST
The test shots were taken on the RF 24-240mm fitted with the dedicated iShoot tripod collar (£40) and mounted on an EOS R5. The duo was mounted on a Gitzo carbon-fibre tripod with an Arca ball head. Shots were taken with the self-timer and Raws processed through Adobe Lightroom with the correct lens profile applied.
24mm
50mm
100mm
150mm
240mm
F/4
F/4
F/5
F/5
F/5.6
F/5.6
F/6.3
F/6.3
F/6.3
F/6.3
F/5.6
F/5.6
F/8
F/8
F/8
F/8
F/8
F/8
F/8
F/8
F/8
F/8
F/11
F/11
F/11
F/11
F/11
F/11
F/11
F/11
F/11
F/16
F/16
F/16
F/16
F/16
F/16
F/16
F/16
F/11
F/16
F/22
F/22
F/22
F/22
F/22
F/22
F/22
F/22
F/16
F/22
F/29
F/29
F/32
F/32
F/32
F/32
F/32
F/32
F/22
“WHERE THE RF 24-240MM WINS IS IN THE SHEER FLEXIBILITY GLEANED FROM ONE LENS, PLUS IT COMES IN AT A FAIR PRICE”
I’m pleased to report that I got an impressive hit rate, with three out of five shots sharp at 1sec and 100% success at 1/2sec. The only other control is a focus/ control ring switchover. Set control and a range of functions can be dedicated to it. With focus selected, the ring does nothing (at least not on the EOS R5) unless manual focus is set on the camera. When the Lens Electronic MF menu item is used in single-shot AF, you get manual focus with or without magnification when the shutter release is partially held down. It’s a pity the focus switch doesn’t give manual focus directly. Using a Nano AF motor, this lens’ autofocus is impressive. It’s almost silent, judder-free and responsive, so nothing to complain about here. Optically, the 24-240mm proved a decent performer. At 24mm, central sharpness was good wide open and
at f/5.6. This improved stopping down to f/8 and f/11, while quality dropped off at f/16 and f/22. Corner and edge quality was less crisp at the wide apertures – and even stopping down to f/11 didn’t help much. There was colour fringing, too. That pattern of performance was repeated at 35mm and 50mm, although the fall-off in performance at the two smallest apertures was more marked. At 100mm, sharpness and contrast at f/5.6 rated highly at the centre of the frame, while the edges held up. Stopping down to f/8 boosted image quality further. This and f/11 were the best two settings for across-the- frame image quality, while sharpness at f/22 and f/32 was average. Moving out to 150mm, sharpness at the maximum aperture was less impressive than that seen at the tested shorter focal lengths, but
quality was more even across the frame. Setting f/8 or f/11 produced a hefty step up in detail rendition – before quality drifted off at the smaller values. I expected 240mm would be worse still, but that wasn’t the case. Quality at f/6.3 and f/8 was more than acceptable. Stopping down to f/11 improved the corners and edges. The smaller values followed the same pattern of the shorter focal lengths, and diffraction had a significant negative impact on sharpness.
The lens suffers from distortion and vignetting. While JPEGs are corrected in-camera, Raws need processing with a dedicated profile. Uncorrected Raws show vignetting and barrel distortion at 24mm. This became less obvious by 35mm, and
pincushion distortion takes over from 50mm. The downside with the 24mm setting is you lose millimetres with the required correction. This was confirmed by comparing shots taken at the 24mm setting of the zoom with Canon’s RF 24mm prime.
Verdict Superzooms are an acquired taste. If you’re going to invest in one, you have to accept that optically it’s never going to surpass a prime or fast-aperture zoom. That said, the Canon RF 24-240mm f/4-6.3 IS USM does appeal. Its optical performance is not going to pull up any trees, but keep to the wider to mid apertures and image quality is more than acceptable – with some judicious processing, a lot can be squeezed out of the Raws. Obviously, it’s not going to outperform the RF 24-105mm f/4 and RF 70-200mm f/2.8, for example, but those are both L-series lenses. Their combined cost is three times the price of this superzoom. Where the RF 24-240mm wins is in the sheer flexibility gleaned from one lens, plus it comes in at a more-than-fair price. PROS 10x focal length range, control/focus ring, whole zoom range covered quickly, Nano USM AF, five-stop benefit image stabiliser CONS No lens hood supplied as standard, needs stopping down for good edge/corner sharpness, no dust/ moisture resistance, distortion correction means you don’t get a true 24mm, manual focus has to be set from the camera menu
THE POWER OF TEN These two shots taken from the same spot at opposite ends of the zoom range show the practical benefits of the 10x RF 24-240mm
44 Photography News | Issue 113
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