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Monday, July 20, 2015

Canon EF 600mm f/4 DO IS Lens Patent

Canon EF 400mm f/4 DO IS II lens

Canon's announced their first Diffractive Optices lens, the EF 400mm f/4 DO IS in 2001. It was a revolutionary lens with a dramatic weight reduction for that speed and focal length lens. I bought the glass a few years later and it quickly found a place in my equipment bag. The only slight drawback of the lens was it's not one of Canon's sharpest.

The EF 400mm f/4 DO IS II was announced late last year and this time I immediately placed my pre-order and have subsequently taken the lens on wildlife photography shoots around the globe. This second generation lens is a big improvement and definitely produces sharp images. Nikon has finally seen the light and is trying to catch up with their own version of DO lens, called Phase Fresnel.

Below is another new Canon patent discovered by Egami, the Japanese blog, for the EF 600mm f/4 DO lens. I will be most interested in acquiring this piece of glass if Canon decides to put it into production. You can see my works taken with the EF 400mm f/4 DO IS II on

Patent Publication No. 2015-11171 (Google Translated)

  •     Published 2015.1.19
  •     Filing date 2013.6.28

Example 2

  •     Focal length 588.30mm
  •     Fno. 4.12
  •     Angle of view 2.11 °
  •     Image height 21.64mm
  •     Lens length 397.80mm
  •     BF 2.02mm
  •     Positive ShiboTadashi
  •     Inner focus
  •     Vibration control

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