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

ExampleFocal distanceFno.Half angleImage heightOverall length of the lensBF
One294.004.144.2121.64239.0783.42
Two24.482.8641.4721.6492.0038.00
Three51.701.3022.7121.6494.0137.50
Four294.004.144.2121.64240.0082.95
Five6.15 20.45 71.282.88 3.71 3.6930.34 9.98 2.893.6084.11 86.12 90.4111.74 15.68 8.50
Six293.974.144.2121.64239.9885.34

Source: [Egami]

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