Observant Japanese lens patent blog An Image on a Sensor was first to point to a patent including embodiments for a great number of missing RF-mount primes. The patent – published earlier today but filed 18 months ago – includes the long-missing RF 24mm f/1.4 and f/1.8; RF 50 f/1.4; RF 35mm f/1.8 (non-macro); and RF 28mm f/1.8.

The 24mm f/1.4 looks particularly interesting, as it appears to contain more than 20 elements in at least six groups, which – at 120 mm long – appears to be about 30 percent larger than even the 24mm Sigma Art f/1.4.

Canon lacked inexpensive glass at the time these patents were filed in July of 2019. With the introduction of their first full frame mirrorless camera, the EOS R, Canon had an intermediate mirrorless camera but a set of crazily expensive professional lenses. Only in 2020 did a few f/1.8 lenses make it out to make the RF system appear to make more sense for people purchasing bodies like the EOS RP.

The 50mm F/1.4 would be the first f/1.4 prime at that focal length since the venerable and much-maligned series EF-mount 50mm F/1.4 USM from 2008. That lens launched well before the “coatings revolution” that vastly increased image quality, but aside from that disadvantage had the unfortunate tendency to break apart. The absence of a adequate-quality f/1.4 50mm lens has been subject of an inside joke meme among internet forum dwellers.