[Patent] New Canon Phase-Detection AF Method With Higher Accuracy And Smaller Pixel Size (for the next mirrorless camera?)

Egami (machine translated) found a Canon patent for an improved phase-detection AF. Higher accuracy is obtained by better propagation of light. The patent text also suggests, the method should improve accuracy when light is falling in with a low-angle incident. I found another thing very interesting: the patent refers to smaller pixel size, i.e. you can pack more pixel on the sensor. So, given that a phase-detection AF is particularly useful on a mirrorless camera, could that indicate that Canon is working on a higher resolutions sensor (with an improved AF) for its more pro-oriented mirrorless camera that we expect to be announced later this year?

  • Patent Publication No. 2012-151215
    • 2012.8.9 Release Date
    • 2011.1.18 filing date
  • Existing techniques
    • JP 2002-314062
    • Conventional techniques beam separation is insufficient, Ranging Accuracy is poor
      • Scattering effects due to wiring
      • The smaller the angle of incidence, it is difficult to detect
      • Smaller pixel size, the value of F becomes larger microlenses (dark), they spread the light next to almost the same in the size of the image pixel size and pixel diffraction
  • And waveguide
    • The waveguide, depending on the angle of incidence of the light flux, there is a characteristic (waveguide mode) is different states of light propagation in the waveguide
  • Canon ‘s patented
    • Consisting of waveguide waveguide and vice
      • Guiding light of two different incident direction: waveguide
      • Vice waveguide: one for each waveguide comprises a waveguide two sub-
    • Can be detected by the photoelectric conversion unit specific, the incident light at a particular angle
    • Impact of wiring
      • The incident light to propagate the core portion of the waveguide, reducing the impact of wiring
    • Low-angle incident light, by using the corresponding waveguide mode depends on the incident direction
    • Small pixel size, support by limiting the distribution of the emitted light
      • Achieved by suppressing the spatial width confinement in the waveguide propagation of light sub-


[Rumor] New 35mm f/1.4L II Soon To Be Announced?

The rumor comes from CR. Not a new rumor, and a plausible one. It’s said that three prototypes of the next iteration of the 35mm f/1.4L are already out in the wild, given to selected photographers for testing purposes. The new 35mm should then be announced after Canon has started mass production and shipping of the 24-70mm f/2.8 II USM. Finally, the 35mm f/1.4L II USM should be announced in 2012 and be available for the masses in 2013. Last month I reported about a patent that most probably refers to the new 35mm, check it to know more about the optical properties of this lens.

The actual 35mm f/1.4L USM has a price tag around $1,344 (click on the shop name to learn more): B&H Photo, Adorama, Amazon USA, Amazon CA, KEH Camera, Canon CA, Canon USA

[Patent] Canon Patent For Improved Phase Detection Auto Focus

Phase Detection AF

Egami (machine translated) found a patent by Canon regarding an improved Phase Detection Auto Focus. Such a “hybrid” autofocusing system has been featured on the Rebel T4i/650D and the recently announced EOS M. The patented technology aims at improving speed and accuracy. Is this the AF system that Canon will implement on its next, more pro-oriented mirrorless camera, expected to be announced later this year?

  • Patent Publication No. 2010-60771
    • 2010.3.18 Release Date
    • 2008.9.3 filing date
  • Existing techniques
    • Patent Publication No. H11-281878
    • Different lengths of baseline using the AF sensor
      • F2.8 sensor: high focusing accuracy
      • Can detect a wide range of defocus amount (the amount of deviation of focus): F5.6 sensor
      • After roughly at F5.6 sensor is focused, making focus F2.8 sensor with high accuracy
    • Drawback
      • Depending on the timing F2.8 sensor is not used, focusing accuracy is not good
  • Canon’s patent
    • Different lengths of baseline using the AF sensor
      • Because of the defocus amount detection range is limited, must search as duplicate detection range
      • By using the F5.6 sensor, within a limit not exceeding the amount of defocus, it is possible to focus lens is driven at high speed
    • If the Live View
      • The image plane using phase difference AF
      • Focus lens is driven at high speed
        • Using the central pixel: When low-intensity
        • Using the neighboring pixels: When high-intensity
Imaging surface phase detection AF
[via Egami]

[Patent] Canon 135mm f/2.8 and a 180mm f/3.5 Using An Apodization Filter

135mm f/2.8
180mm f/3.5

Japanese site Egami (machine translated) spotted another patent filed by Canon. This time it is about a 135mm f/2.8 and a 180mm f/3.5 lens. The news are an apodization filter that should help provide a more pleasant bokeh.

  • Patent Publication No. 2012-128151
    • 2012.7.5 Release Date
    • 2010.12.15 filing date
  • Example 1
    • 137.2mm – f = 135.0 focal length
    • Fno 2.83 -. 3.90
    • 9.1 deg half each painting.
    • Image height 21.60mm
    • 186.7mm – 150.0 full-length lens
    • BF 47.4 – 80.7mm
    • Lens Construction 10 elements in 7 groups sheet
    • 1 UD glass sheet
    • 0.25 times the maximum magnification ratio
  • Example 6
    • 179.1mm – f = 180.0 focal length
    • Fno 3.50 -. 4.00
    • 6.9 deg half each painting.
    • Image height 21.60mm
    • 218.0mm – 199.8 full-length lens
    • BF 70.0 – 89.8mm
    • Lens Construction 11 elements in 7 groups sheet
    • 1 UD glass sheet
    • 0.11 times the maximum magnification ratio
  • (Bokeh) out of focus look of the important
  • Apodization filter
    • The periphery of the filter transmittance is reduced
    • Added to the luminous flux intensity distribution
    • Bokeh is beautiful and the outline of the
  • Apodization element variable
    • If the liquid of same refractive index as the shape of the interface, no variation occurs in aberration
    • To be the same refractive power of the two liquids, the Abbe number is difficult
  • Canon‘s patented
    • Variable element shape
      • Voltage is applied, changing the shape of the interface
      • Obtain the effect of apodization
      • Varying refractive power, the Abbe number
    • To reduce the time variable aberrations of shape
      • By a twist of the material performed, to optimize the absorption coefficient, to suppress the generation of aberration to moderate the curvature of the interface
      • To reverse the two materials (such as liquid), the amount of chromatic aberration, do the negation
      • Suppress the two materials (such as liquid), refractive index, the difference between the Abbe number
    • The entire feeding (with floating)


[Patent] Canon Files Patent For 600mm f/5.6 and 800mm f/5.6

600mm f/5.6 DO
800mm f/5.6 DO

Egami (machine translated) found a patent filed by Canon for a 600mm and a 800mm f/5.6 lens using diffractive optical elements.

  • Patent Publication No. 2012-123152
    • 2012.6.28 Release Date
    • 2010.12.8 filing date
  • Example 1
    • Focal length f = 584.99mm
    • Fno. 5.80
    • Half angle of 2.12 deg.
    • Image height 21.64mm
    • Length 360.03mm
    • BF 94.84mm
    • 17 pieces in 10 groups Lens Construction
    • 3 UD glass sheet
    • One fluorite
    • A surface diffraction plane
  • Example 3
    • Focal length f = 779.00mm
    • Fno. 5.80
    • Half angle of 1.59 deg.
    • Image height 21.64mm
    • Length 462.02mm
    • BF 120.29mm
    • 17 pieces in 10 groups Lens Construction
    • 2 UD glass sheet
    • Two fluorite
    • A surface diffraction plane
  • Low dispersion material with anomalous partial dispersion
    • To be effective in the correction of chromatic aberration
    • Specific gravity is large (heavy)
      • 3.18 fluorite
      • FK01 3.63
      • The specific gravity of small anomalous partial dispersion glass material
        • FK5 2.46
        • BK7 2.52
    • Surface may be damaged easily
    • FK01 is fragile due to temperature changes and large diameter
  • Diffractive optical element (DOE)
    • To be effective in the correction of chromatic aberration
    • Is generated by unwanted light flare and ghosting
  • Canon’s patented
    • Become positive from negative to DOE
    • DOE to place the position is hard to unwanted light incident

[Patent] New Canon 44x (24-1060mm) Superzoom for Compact Cameras


Egami (Google translated) spotted another patent by Canon. This time it’s for a 44x (24-1060mm equivalent) superzoom for a compact camera. Egami suggests it will be featured on Canon’s Powershot SX series. This zoom will plausibly compete with the 42x zoom mounted on the Nikon Coolpix P510. The new Canon super-zoom features 13 elements in 10 groups, including two four-sided aspherical elements (see more specs below). A few excerpts: To compensate for aberration across the entire zoom range […] Canon seems to have constantly working on improving the performance using the fluorite. And more:

P510 employs a 1/2.3 type imaging element, the actual focal length is 4.3-180mm (24-1000mm converted). Canon’s patent will be equivalent to 24-1060mm and so rate 4.3-190mm, most will not change the zoom factor and feel of the P510. In the catalog specs, the difference between 42 times and 44 times might actually be important.

Patent summary:

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