Canon Patent - EF-M 55-300mm f/4.5-5.6 DO IS Lens

Canon EF 600mm f/4 DO BR lens

Canon has a strong lead in Diffractive Optics lens technology. They first introduced the EF 400mm f/4 DO IS back in 2001. I bought the lens in mid 2000s and made it my favorite wildlife photography glass for handheld shots. It was not the sharpest lens in Canon's lineup but I was willing to trade that for the unmatched mobility and flexibility the lens offered.

In September 2014, Canon released the EF 400mm f/4 DO IS II and the compromise was gone. The lens has 4 stops IS compensation, is tack sharp and still offers superb mobility. Canon demonstrated the EF 600mm f/4 DO BR lens recently at the Canon Expo in September, 2015.

Last month, Canon filed for a EF-M 600mm f/5.6 DO IS patent. Now, Egami has discovered another new Canon patent. This time it is for a EF-M 55-300mm f/4.5-5.6 DO IS lens. I am a bit puzzled how the DO version of these lenses would work in a mirrorless camera design that is already small, lightweight and consumer grade, unless Canon is planning to announce a professional grade, full frame mirrorless camera some time in the future.

Patent Publication No. 2015-232674 (Google Translated)

•     Published 2015.12.24
•     Filing date 2014.6.11
•     Zoom ratio 5.27
•     Focal length 55.04 135.00 290.01
•     F-number 4.60 5.18 6.30
•     Angle of view 13.94 5.78 2.70
•     Image height 13.66 13.66 13.66
•     Overall length of the lens 136.00 175.46 192.00
•     BF 35.50 35.50 35.50

Canon Patent - EF-M 600mm f/5.6 DO IS Lens

The Japanese photography site Egami uncovered another new Canon patent, the EF-M 600mm f/5.6 DO IS. I am quite comfortable in predicting this patent will most probably never make it to market as is. The thought of a 600mm DO lens mounted on the EOS-M camera can only bring ridicule but it may be modified to fit the future Canon full frame mirrorless camera.

This is clearly Canon's way of staking out their intellectual property by patenting this invention. The current EF 400mm f/4 DO IS II is my favorite Diffractive Optics lens for wildlife photography but there is a chance the EF 600mm f/4 DO BR lens might join its smaller brother next year.

Patent Publication No. 2015-215437

•     Published 2015.12.3
•     Filing date 2014.5.9
•     Focal length 585.00
•     F-number 5.74
•     Half angle (in degrees) 1.34
•     Image height 13.66
•     Overall length of the lens 299.25