Expectations for Performance of the Canon RF 28-70mm f/2L: Canon’s “Halo Lens” in a Golden Age of Optics
Never before has there been so much promise for superb optical designs. Both Nikon and Canon are pulling out all the stops to deliver a number of ultra high performance lenses made possible by the design flexibility of their respective mirrorless lens mounts.
Canon and Nikon know well that Sony is the company to beat, Sony having gobbled up market share far and wide from many segments of the photographic community. What to do in such a competitive situation? Build cameras that are better ergonomically and build truly outstanding lenses. That latter point is the only way out IMO—camera bodies come and go, but the very best lenses can be a compelling reason to switch, and a longer term investment.
Just as the Nikon NIKKOR Z 58mm f/0.95 Noct S is fittingly the halo lens* for Nikon, Canon has chosen a clever “bread and butter lens” approach by serving up an ultra high performance f/2 zoom lens in the critical 28 to 70mm range. It is a lens that sells the camera all by itself, for certain types of photography (wedding and anything like it).
While the about $2999 Canon RF 28-70mm f/2L is costly indeed, the bright f/2 aperture means that most shooters can dispense with prime lenses in that range—which is a big win in multiple ways including simplicity, avoiding the need to change lenses, lighter total travel load, the convenience of a zoom (fewer missed shots!), etc.
Not only is the lens bright, being f/2, but the new Canon mirrorless design ought to deliver total illumination over the frame that is effectively 1/3 to 1/2 stop brighter in the outer zones than the f/2 aperture suggests (versus an equivalent DSLR design at f/2).
The MTF chart for the Canon RF 28-70mm f/2L shows outstanding contrast for coarse and fine structures wide-open. It’s so good wide open at f/2 that it is fair to say that it is in Zeiss Otus territory. That’s incredible, and at f/2.8 and f/4 it ought to get even better. At any aperture, it ought to be be an entirely new experience for Canon shooters.
Meanwhile, Nikon has apparently decided against f/2 in a midrange zoom, because the Nikon Z lens line roadmap shows no such offering even into year 2021. Nikon’s Nikon NIKKOR Z 24-70mm f/2.8 S offers a wider zoom range (a big plus) and surely a much smaller and lighter form factor, but the “hit” is being f/2.8, a full stop less bright as well as having reduced subject isolation chops. Methinks that Canon wins big with the 28-70/2 strategy in certain segments, at least for now.
* A halo product is one which draws attention to the entire product line offering by virtue of something exceptional, e.g. the Apple iPhone X.