The diffractive optics related patents continue to appear from Canon. This time we get a patent that covers both a 300mm f/2.8 DO and a 400mm f/2.8 DO.
We think a slew of diffractive optics super telephotos are on the way for the RF mount and these two optical formulas may find their way to the RF mount in 2020. Perhaps alongside an EOS R version of the EOS-1D X Mark II.
As Canon News points out, the back focus on a super telephoto lens is quite large, so these could easily be RF mount lenses.
Japan Patent Application 2018-189878
Focal distance: 392.58
F number:2.91
A half field angle: 3.15
Image height: 21.64
Length of the lens: 363.53
BF: 59.15
Focal distance: 293.40
F number: 2.91
a half field angle: 4.22
Image height: 21.64
length of the lens: 274.00
BF: 59.35
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