Patent: 400 f/4, 300 f/4, 200 f/5.6

New Lens Formula Patents
A new 400 f/4L IS non-DO would probably be a very welcomed lens. However, it will probably depend on the price of the 200-400 f/4L IS 1.4x ($8000+ I predict) as to whether or not it ever sees the light of day. The 200 f/5.6 is a strange one.

Patent Publication No. 2012-22105

• 2012.2.2 Release Date
• 2010.7.14 filing date

Example 1

• 392.00mm focal length
• Fno 4.12
• 3.15deg half angle of view.
• Image height 21.64mm
• Length 279.32mm lens
• BF 64.82mm
• 15 sheets of 12 group configuration
• An aspherical surface
• Inner focus
• Telephoto ratio 0.71

Example 3

• 200.00mm focal length
• Fno 5.77
• 6.18deg half angle of view.
• Image height 21.64mm
• Length 180.00mm lens
• BF 54.98mm
• 6 lenses in 5 groups configuration
• Telephoto ratio 0.90

Example 4

• 294.00mm focal length
• Fno 4.14
• 4.21deg half angle of view.
• Image height 21.64mm
• Length 239.85mm lens
• 14 images in 9 groups configuration
• An aspherical surface
• Inner Focus
• Telephoto ratio 0.815
• Telephoto lens
• Stretch the focal length, and miniaturized, on-axis chromatic aberration and lateral chromatic aberration occurs
• Tele photo lens type refers to the overall length is shorter than the focal length
• And telephoto ratio refers to the value obtained by dividing the focal length the total length
• Canon's patent
• Using the lens refractive index distribution

 Source: [EG]

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