Canon diffractive optics patents are making a big come back!
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Fred Miranda
Registered: Dec 31, 2001
Total Posts: 18005
Country: United States

Since 2001, with the release of the Canon 400mm f/4 DO IS, we havenít seen the use of DO (diffractive optics) in super telephoto lenses.
Even though the 400mm DO IS was a successful lens because of its size and weight, due to a somewhat reduced contrast, it could not quite live up to the quality of its larger and heavier "Fluorite" counterparts.

Canon has been filing more DO super telephoto patents recently with the 400mm f/2.8 DO and 600mm f/4 DO. And now, we are finding patents for the 600mm f/5.6 DO and 800mm f/5.6 DO filed. Maybe this means we can
expect a new surge of DO technology in super telephoto lenses in the near future?

I for one would love to carry around a Canon 800mm f/5.6 weighting 6 pounds!
To see the recent DO patents click on the links below:

Canon 600mm f/5.6 DO and Canon 800mm f/5.6 DO patents

Canon 400mm f/2.8 DO and Canon 600mm f/4 DO patents



cookie99
Registered: Jul 24, 2005
Total Posts: 20
Country: Australia

Thanks Fred, interesting developments.



Andrew Welsh
Registered: Jan 20, 2007
Total Posts: 4973
Country: United States

Definitely interesting, the 400/2.8 is already pretty heavy.