Canon recently has filed two new Cinema zoom lens patents in Japan: Canon CN-E 18-85mm f/2.8 Lens and Canon CN-E 15.5-47mm f/2.8 Lens.
Patent Publication No. 2015-4917
Published 2015.1.8
Filing date 2013.6.24
Example 1
Zoom ratio 2.80
Focal length 16.00 29.68 44.80
F number 2.80
Half angle (in degrees) 43.15 26.81 18.51
Image height 15.00
Overall length of the lens 263.54
BF 39.04
Example 2
Zoom ratio 4.50
Focal length 18.50 45.61 83.25
F number 2.80
Half angle (in degrees) 39.04 18.20 10.21
Image height 15.00
Lens length 263.78 263.78 263.78
BF 46.93 46.93 46.93
Patent Canon
5-group zoom of positive and negative negative-positive-positive
Inner focus (part of the first group)
Inner zoom
via: EG
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