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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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