Canon Patents EF & EF-M 50-300mm f/4.5-5.6 DO STM

According to the Egami Blog, Canon has patented an EF 50-300mm f/4.5-5.6 STM with diffractive optics and a similar EF-M version.

Description of Patent

• Patent Publication No. 2016-57444
• Published 2016.4.21
• Filing date 2014.9.9
• EF Version
• Zoom ratio 5.59
• Focal length 51.77 135.00 289.53
• F-number 4.65 5.05 5.85
• Half angle of view (degrees) 14.78 5.78 2.70
• Image height 13.66 13.66 13.66
• The total lens length 126.05 169.37 184.15
• BF 35.50 35.50 35.50
• EF-M Version
• Zoom ratio 5.90
• Focal length 49.13 135.00 290.00
• F-number 4.65 4.95 5.85
• Half angle of view (degrees) 15.54 5.78 2.70
• Image height 13.66 13.66 13.66
• The total lens length 108.00 152.12 168.00
• BF 15.69 15.69 15.69