Richard CanonNews / Wednesday, November 15, 2017 / Categories: Canon Patents Another super-telephoto diffractive optic patent This patent deals with joining an aspherical element with a DO element group. In this patent is listed embodiments for a 300 2.8 IS DO and another 400 4.0 IS DO. Canon continues to work on improving the diffractive optical super telephotos, and maybe just maybe we'll see a 300mm DO similar to what Nikon has come out with. Read more US Patent Application 20170168269 Previous Article E-Photozine: TS-E 50mm Macro Tilt-Shift Review Next Article New flash rumored aimed at small cameras and mirrorless Print 5294 Leave a comment Name: Please enter a name. Email: Please enter an email address. Please enter a valid email address. Comment: Please enter comment. I agree This form collects your name, email, IP address and content so that we can keep track of the comments placed on the website. For more info check our Privacy Policy and Terms Of Use where you will get more info on where, how and why we store your data. You must read and accept this rules. Add comment