Canon Patents

Patent: Canon EF 300mm f/4L IS & Others

A patent for a new EF 300mm f/4L IS has appeared. Other optical formulas appearing in the patent are 24mm f/2.8 and 50mm f/1.3 with variable diffractive index elements which help correct some aberrations (thanks Keith).

Patent Publication No. 2015-28551 (Google Translated)

  • Published 2015.2.12
  • Filing date 2013.7.30

Example

Example Focal distance Fno. Half angle Image height Overall length of the lens BF
One 294.00 4.14 4.21 21.64 239.07 83.42
Two 24.48 2.86 41.47 21.64 92.00 38.00
Three 51.70 1.30 22.71 21.64 94.01 37.50
Four 294.00 4.14 4.21 21.64 240.00 82.95
Five 6.15 20.45 71.28 2.88 3.71 3.69 30.34 9.98 2.89 3.60 84.11 86.12 90.41 11.74 15.68 8.50
Six 293.97 4.14 4.21 21.64 239.98 85.34

Source: [Egami]

cr

Comments are closed.