skip to Main Content

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]

 

Back To Top

Notice

This website or its third-party tools use cookies, which are necessary to its functioning and required to achieve the purposes illustrated in the cookie policy. If you want to know more or withdraw your consent to all or some of the cookies, please refer to the cookie policy.
By closing this banner, scrolling this page, clicking a link or continuing to browse otherwise, you agree to the use of cookies.