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Friday, June 20, 2014

Canon Patent - EF 400mm f/4 DO IS

Canon EF 400mm f/4 DO IS lens

* * *  Read the latest post on EF 400mm f/4 DO IS II lens  * * * 

A new patent for the Canon EF 400mm f/4 DO IS has been uncovered by Egami of Japan. The current EF 400mm f/4 DO IS is my favorite prime Super Telephoto lens but its design and technology is 'aging' after the initial introduction in late 2001. The current lens is in my equipment bag on all my photo shoots. You can see my works on

 Patent Publication No. 2014-109700
  •         Publication date 2014.6.12
  •         Filing date 2012.12.3

 Example 1
  •         Focal length f = 392.00-381.59-332.99mm
  •         Fno.
  •         Half angle ? = 3.16-3.10-2.81 °
  •         Image height Y = 21.64mm
  •         The overall length of the lens 292.02mm
  •         BF 105.64mm

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