Patent for RF 100-500, 70-200 Revealed, Includes Crop Zoom

Just when patents get published is based largely on statutory time periods, and sometimes the products themselves come out before publications, as is the case with the well-liked Canon RF 100-500 and the two 70-200mm lenses Canon added to the RF lineup. Today the patent finally squirted out of Japan’s patent office (via An image on a sensor).

In addition to those three lenses, other embodiments were explicitly laid out, including some cheaper, darker zoom lenses ranging up to f/8 and, very interestingly, a crop 55-250mm with variable aperture between 4.5 and 6.3 (roughly).

The patents were filed back in 2019, back when the M mount series didn’t appear in quite so much trouble. The crop sensor zoom may have been intended for that mount, or – to the joy of the disheartened RF crop boosters – it could mean that something in the crop sensor flavor may have been in the planning stages back then.

Looking at Canon’s published designs for the 100-500 zoom, the second embodiment of the patent matches the lens arrangement precisely.

The third embodiment matches exactly the RF 70-200 f/2.8, and the first embodiment matches the RF 70-200 f/4.