Canon Patent Application: DO Supertelephotos

Another patent for diffractive optics (DO) super telephotos has appeared.  This seems to be a subject of ongoing R&D inside of Canon, with several patent applications listed for these lenses using diffractive optics.

There was a rumor about super telephotos for the RF mount using Diffractive Optics, perhaps this is related.  For supertelephoto lenses, the back focus is so large, that the lens could be made for just about any mount.

This patent application describes two lens embodiments, one for a 300mm 2.8 and another for a 400mm 2.8 DO supertelephoto.

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

Japan Patent Application 2018-189878

Richard CanonNewsRichard CanonNews

Richard has been using Canon cameras since the 1990s, with his first being the now legendary EOS-3. Since then, Richard has continued to use Canon cameras and now focuses mostly on infrared photography. Richard is the founder and editor of CanonNews since 2017, and has worked as a writer on CanonRumors and other websites in the past.

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