Canon filed a new patent “400mm F5.6 reflex-mirror lens with an electrochromic ND filter for APS-C DSLR camera”. Since the patent was filed so we can expect its arrival somewhere at any point of 2018. No further detail has been included yet.
Specification and lens arrangement of embodiment 1 Focal length: 400 mm F No.: 5.6 2ω: 1.96 Image height: 13.66 mm Back focus: 33.07 mm Lens
Continue reading Canon Filed 400mm F5.6 lens Patent for APS-C DSLR