You are browsing the archive for Patents Archives - CanonWatch.

April 13, 2015
Posted in Patents

Sigma patent for 400mm f/2.8 OS Sport Lens



Egami (translated) spotted an interesting patent filed by Sigma. It refers to a 400mm f/2.8, image-stabilized lens. This lens will be part of Sigma’s “Sport” line-up.

  • Patent Publication No. 2015-64436
    • Published 2015.4.9
    • Filing date 2013.9.4
  • Example 1
    • Focal length 390.00mm
    • Fno. 2.91
    • Total angle of view 2ω 6.29 °
    • Image height Y 21.63mm
    • Overall length of the lens 353.00mm
    • Positive, positive positive and negative negative 5-group configuration
    • Inner Focus (fourth group)
    • Anti-vibration (part of the fifth group)
April 1, 2015
Posted in Patents

Canon Patent for new automatic Vignette Correction Processing Algorithm


Egami (translated) spotted a patent filed by Canon for an image processing algorithm that corrects lens vignetting by varying the exposure time according to the image height, i.e. applying different exposure times to different spots in the image area.

One thing to note, in my opinion: this patent implicitly also refers to a new sensor tech. Some excerpts from the patent description:

The present invention relates to the control method of the imaging device which has an image sensor in which exposure control is possible for every region, and the Method of amendment of an image.

In the imaging device which photos an object by acquiring an optical image via a lens, in the image of the photoed object, what is called a light-falloff-at-edges phenomenon in which light volume is deteriorated occurs as it goes to an image periphery from the central part of the image.

It is known that a light-falloff-at-edges phenomenon will be decided by the relation of the characteristic of the lens with which an imaging device is provided, and the characteristic of a solid state image pickup device. Specifically, it is a relation with the position of the solid state image pickup device to an effective image circle (region where light hits uniformly), and the amount of light falloff at edges is decided uniquely. However, it will be the requisite that the effective pixel center of a solid state image pickup device and the optical axis center of a lens are corresponding in this case. It is dependent also on the f-stop of a lens, and the amount of light falloff at edges has an omission condition of light volume remarkable in the opening and small diaphragm side. In the opening side, although the incident light in a lens center enters as a general lens characteristic with circular light flux, since the incident light in the corner of a lens always passes along the corner, light will be kicked, incident light becomes the light flux of elliptic form, and light volume is deteriorated.

  • Patent Publication No. 2015-56709
    • Published 2015.3.23
    • Filing date 2013.9.11
  • Patents
    • I varying the exposure time for each area
      • The exposure start falling apart, batch read
      • At the same time in the start of exposure, read apart
    • I lengthen the peripheral of exposure time

What do you think?

March 9, 2015
Posted in Patents

Canon Patent for 100x Zoom Compact Camera (24-2400mm equivalent)


Will this patent (spotted by Egami) ever hit the market? If it does it will probably yield a new Powershot camera with a wobbling 100x zoom. The patent refers to a 1/2.3″ sensor and an equivalent focal length of 24-2400mm.

  • Patent Publication No. 2014-174524
    • Published 2014.9.22
    • Filing date 2013.3.13
  • Example 4
    • Zoom ratio 98.52
    • The focal length f = 3.07 53.41 302.40mm
    • Fno. 1.85 8.14 9.00
    • Half angle ω = 36.2 2.40 0.50 °
    • Overall length of the lens 110.05mm
    • BF 12.67 27.40 5.19mm
    • 4-group zoom of positive and negative, positive
    • Inner zoom (the second group, the third group)
    • Rear focus (fourth group)
    • Anti-vibration (third group)

Do you think Canon will produce a Powershot with a 100x zoom anytime soon?

March 5, 2015
Posted in Patents

Canon Patent for 12-32mm T3.5 and a 15-47mm T2.8 Cinema Lenses


Egami (translated) spotted a patent for two Cinema lenses, a 12-32mm T3.5 and a 15-47mm T2.8 lens.

  • Patent Publication No. 2015-34858
    • Published 2015.2.19
    • Filing date 2013.8.8
  • Example 1
    • Zoom ratio 2.50
    • The focal length f = 12.50 18.75 31.25mm
    • Fno. 3.50
    • Half angle ω = 51.21 39.67 26.45 °
    • Image height Y = 15.5mm
    • Overall length of the lens 193.59
    • BF 42.84
  • Example 2
    • Zoom ratio 2.81
    • Focal length 16.00 26.88 45.00
    • Fno. 2.80
    • Half angle of 44.18 30.05 19.06
    • Image height Y = 15.5mm
    • Overall length of the lens 247.38
    • BF 43.27
  • Canon patent
    • Negative positive and negative positive 4-group zoom
    • Inner zoom (the second group)
    • Inner focus (rear group of the first group)
February 27, 2015
Posted in Patents

Canon Patent for 9-18mm Ultra-Wide Angle Lens for EOS M


Egami (translated) spotted a patent for an EF-M 9-18mm f/3.5-4.5 STM lens for the EOS M system. A bit weird since there is already the excellent EF-M 11-22mm f/4-5.6 IS STM lens. I guess this is just one of the many patents Canon is filing and not a lens that will hit the market anytime soon.

  • Patent Publication No. 2015-34892
    • Published 2015.2.19
    • Filing date 2013.8.9
  • Example 1
    • Zoom ratio 1.90
    • The focal length f = 9.22 14.67 17.50mm
    • Fno. 3.45 4.02 4.63
    • Half angle ω = 55.92 42.90 37.92 °
    • Image height Y = 13.63mm
    • Overall length of the lens 94.76 85.16 91.16mm
    • BF 13.06 15.35 13.60mm
    • Negative positive and negative positive 4-group zoom
    • Inner Focus (third group)
    • Video support
February 25, 2015
Posted in Patents

Canon Patent for Foveon Style Multilayer AF Sensor


Egami (translated) spotted a patent for a new AF sensor. The patent describes a Foveon-like, multilayer sensor:

Patent Publication No. 2015-37217

  • Published 2015.2.23
  • Filing date 2013.8.12

Canon patent

  • AF sensor
  • In the depth direction, I comprises a first layer, the second layer, the photoelectric conversion portion of the third layer
  • The second layer is for monitoring, detecting the amount of light that is received in real-time, to control the accumulation time
  • The third layer in a bright environment, the dark environment so that the use of the first layer, sensitivity can be switched
  • Furthermore, in a dark environment is used by adding the first and third layers