With the advent of the RF mount, Canon entered a new realm of lens design, with some of the most extreme designs ever seen for full frame cameras. Nonetheless, it seems the company is also exploring more measured and pragmatic designs as well, with some very interesting f/4 zoom lens designs emerging in a recent trio of patents.
Canon recently patented a trio of three new f/4 zoom lens designs, including:
- 15-70mm f/4
- 13-60mm f/4
- 18-100mm f/4
Given the associated angles of view in the patents and their corresponding focal lengths, it appears that these are being designed for an APS-C sensor and would thus be for the RF-S mount. The timing is not particularly surprising, given Canon's recent focus on APS-C cameras, with releases like the EOS R7, EOS R50, and EOS R10, as it seems the company is filling out the lower end of their mirrorless line as well. And f/4 lenses for APS-C cameras will likely be both affordable a highly portable. That being said, the appearance of a patent doesn't guarantee a product will make it to market, though I wouldn't be surprised to see one of these lenses eventually.