Four New Canon Telephoto Lens Patents: 2 x 400mm f/4, 600mm f/4 and 800mm f/5.6, all with macro)

Once more Egami (translated) spotted interesting new patents filed by Canon. A 400mm f/4 DO macro 1:1.4, a 400mm f/4 DO macro 2:1, a 600mm f/4 macro 1:1 and an 800mm f/5.6 DO macro 1:1. All lenses feature diffractive optical elements (the DO in the naming)

Self-interpretation and summary, Patent Documents

  • Patent Publication No. 2012-242742
    • Release Date 2012.12.10
    • Filing date 2011.5.23
  • Example 1
    • Focal length f = 788.34mm
    • Fno. = 5.80
    • 2ω = 3.14 ° angle of view
    • Image height 21.64mm
    • 486.00mm length lens
    • BF 110.67mm
    • β = -1.02
    • (The second and third group is for the focus) consists of four groups of positive and negative polarity
    • (One side of the image, such as the most protective glass) x 17 lens elements in 12 groups composed
    • Maximum effective diameter 135.92mm
    • Two two-sided aspherical
    • DOE 1 surface
    • One fluorite
    • Three Super UD glass
    • One low-dispersion glass
  • Example 2
    • Focal length f = 400.00mm
    • Fno. = 4.12
    • 2ω = 6.20 ° angle of view
    • Image height 21.64mm
    • 300.00mm length lens
    • BF 55.00mm
    • β = -2
    • (For the second focus group 2,4) consists of four groups of positive and negative positive negative
    • (One side of the image, such as the most protective glass) x 19 lens elements in 12 groups composed
    • Maximum effective diameter 97.09mm
    • Five 5-sided aspherical
    • DOE 1 surface
    • Two fluorite
    • 1 UD glass sheet
    • One low-dispersion glass
  • Example 6
    • Focal length f = 585.00mm
    • Fno. = 4.12
    • 2ω = 4.24 ° angle of view
    • Image height 21.64mm
    • 350.00mm length lens
    • BF 55.00mm
    • β = -1
    • (For the second focus group 2,4,5) group configuration 6 positive negative positive positive negative
    • (One side of the image, such as the most protective glass) 22 sheets 13 groups lens configuration
    • Maximum effective diameter 142.00mm
    • Four four-sided aspherical
    • DOE 1 surface
    • Two fluorite
    • 1 UD glass sheet
  • Example 9
    • Focal length f = 390.99mm
    • Fno. = 4.12
    • 2ω = 6.34 ° angle of view
    • Image height 21.64mm
    • 256.40mm length lens
    • BF 62.35mm
    • β = -0.7
    • (For the second focus group 2,4) consists of four groups of positive and negative positive negative
    • (One side of the image, such as the most protective glass) x 16 elements in 12 groups lens configuration
    • Maximum effective diameter 94.90mm
    • Four four-sided aspherical
    • DOE 1 surface
    • 2 UD glass sheets
    • Two low-dispersion glass
  • Inner focusing formula
    • Easy to shorten the minimum focusing distance
    • AF is faster
    • Large variations in aberrations
    • Many aberration occurs at close range
  • Inner focusing high-performance formula
    • With a focus group of two or more
    • However, optimization of the parameter is mandatory
    • In the macro range of 0.5 times more difficult to correct aberrations
  • Diffractive optics
    • Shortening of the total length can be
    • Distance of the lens group becomes narrow, the range of movement of the focus group will be limited
  • Canon patent
    • Group before and after the group of positive and negative
    • Inner Focus (and the second group, one of the rear group)
    • By setting multiple focus groups, perform the division of sensitivity, the amount of movement
    • In short travel distance, is focused on the short-range

[via Egami]

 

Follow Canon Watch on: Facebook, Twitter, Google+, RSS, and on 500px
Show the world what you can do with a Canon camera! 1) Submit your picture with a short description on Canon Watch's Facebook page, 2) Like and comment the pictures from other readers on the Photo Stream, 3) A selection of the most liked pictures will be posted every Sunday here on Canon Watch
Please Support Canon Watch! I love to bring you all the latest news about everything that's related to Canon (and to photography). If you like what I am doing here then consider buying your gear by clicking my links to make your purchase. You won't pay a penny more and I get a small commission that helps me keep the site going. Thank you!