Lens Test: Canon RF 28-70mm
Quite the handful, this rather hefty RF lens proves that ‘mirrorless’ isn’t all about the downsizing your glassware
This hefty RF lens proves that ‘mirrorless’ isn’t all about the downsizing your glassware
one of the attractions of Canon’s EOS R and RP full-frame mirrorless bodies is their compact,
lightweight build compared with full-frame DSLRS. To follow suit, the RF 24-105mm f/4l IS USM standard zoom lens shaves off 11mm in length and 95g in weight, compared with its EF L-series counterpart.
By contrast, the RF 28-70mm is a beast. It’s much bigger at 104x140mm, and about twice as heavy, at 1430g. It’s also nearly twice the weight and twice the price of Canon’s top-spec 24-70mm f/2.8 lens, weighing about the same as a 70-200mm f/2.8 zoom. The RF lens’s upscaled build is mainly due to it being a full f-stop faster than most premium standard zooms. The optical elements need a larger diameter to let in more light, as such, the lens has an oversized 95mm filter thread, despite its more limited zoom range with less wide-angle potential. Instead, the design goes all out for premium image quality with minimal distortions in shots.
You could argue that with its f/2 aperture and premium optical design, this zoom lens performs more like four prime lenses with 28mm, 35mm, 50mm and (nearly) 85mm focal lengths. The zoom lens might therefore represent a saving in size and weight, while also reducing the need to swap lenses. Even so, a prime lens with a similar aperture rating would equate to a more compact shooting package around your neck, even if it meant popping a few extra lenses in your bag. The lack of a mount ring makes for a poor balance when using a tripod of monopod.
Canon advertises the lens as being great for travel photos, weddings and
photojournalism. It’s uncomfortably large and heavy for a ‘travel lens’, but it has distinct advantages for the other two uses. Along with zoom versatility for quickly framing compositions, the fast aperture rating enables a tight depth of field, along with fast shutter speeds for freezing motion, even under dull lighting. Freezing camera-shake is more of a challenge, adding another question mark over Canon’s decision not to fit IBIS (in-body image stabilization) to the EOS R and RP.
The top-notch optical design incorporates two ground aspherical elements, two Glass-moulded (GMO) aspherical elements, two UD (Ultra-low Dispersion) elements and one Super UD element. Multiple coatings include SWC (Subwavelength Structure Coating) and ASC (Air Sphere Coating).
Performance
Autofocus is fast but not silent, based on a ring-type ultrasonic system, rather than a stepping motor or Nano USM. Centresharpness is spectacular across the entire zoom range, even when shooting wide-open at f/2, although corner-sharpness at the short end is disappointing. At f/2, bokeh is beautiful with negligible longitudinal or ‘bokeh’ fringing, and wonderfully smooth transitions from sharp to defocused areas.