This patent shows how Canon increased AF point coverage in the Canon EOS 5D Mark IV

Interesting patent that seems to refer to how Canon increased the coverage of Auto-Focus points in the new Canon EOS 5D Mark IV. The image above shows the difference compared to the [shoplink 2431]EOS 5D Mark III[/shoplink]. It’s done by replacing the sub mirrors with laminated diffraction gratings, as in the image below. The laminated gratings alter the reflection angle.

• Patent Publication No. 2016-142769
  • Published 2016.8.8
  • Filing date 2015.1.30
• Canon patent
  • Sub-mirror constituted by the reflection type laminated diffraction grating
  • AF mirror constituted by the reflection type laminated diffraction grating