Canon Patent: 100-400mm f/5.5-7.1 Lens For APS-C Camera
Here is an inetersting Canon patent for a 100-40mm lens. Canon Patent Application 2020-027156 (Japan) discusses optical formulas for a 100-400mm f/5.5-7.1 lens. The interesting fact is that this 100-400mm f/5.5-7.1…