Canon patented a small, high-zoom-ratio lens, which in itself is nothing new. Canon makes a point of patenting everything that could possibly be patentable, including a great proportion of lens designs it will never manufacture. But this patent is interesting in that it establishes Canon’s research and invention in a particular type of complex focus system that Tamron laid a claim to just a week ago.

Both lens patents indicate that groups of elements within the zoom will move at different relative speeds and directions in order to achieve focus while requiring fewer corrective elements to achieve this. Essentially, the new concept in both inventions involves a compound focusing system that no longer relies on one group simply moving forward and back, but rather multiple groups moving in various directions and degrees, depending on the current focal length and the distance of the focal plane.

Once released, if released, these lenses would be great subjects for the tear-down videos done by camera blog sites such as the Lensrentals.com blog, as the complexity of the camming should prove pretty interesting. The cam systems are the rollers that move along spiral-cut openings in internal lens sleeves that cause elements to move back and forth when users rotate a ring.

A picture of a cam system from a LensRentals.com blog post (Canon RF 100-500 tear-down)