Canon Patent for new automatic Vignette Correction Processing Algorithm

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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?

A comprehensive video introduction to the Canon EOS 7D Mark II

CanonUSA on YouTube posted a 6 minutes video about the Canon EOS 7D Mark II. Anything you want to know about the 7D2? The video is likely to give you an answer.

Read more about the EOS 7D Mark II’s highlights: the excellent weather sealing, the highly advanced AF, and the industry leading high ISO performance (have a look here too). All our coverage on the EOS 7D Mark II can be seen here (and there is a lot).

Canon EOS 7D Mark II price check: B&H Photo, Adorama, Amazon USA, Amazon Canada, Canon Canada, Canon USA

7D Mark II

Canon announce 9 new, high performance network cameras

Canon Rumor

Canon press release:

Canon U.S.A. Expands Network Camera Lineup With Introduction Of Nine New Versatile, High Performance Models – Including Three In New “Speed Dome” Category

New Network Camera Models Include Weather and Vandal Resistant Speed Domes with 30x Optical Zoom and 360 Degrees Continuous Rotation, and Multiple Outdoor and Indoor Fixed Dome and Bullet Cameras 

MELVILLE, N.Y., March 31, 2015 – Canon U.S.A., Inc., a leader in digital imaging solutions, has introduced nine new Network Cameras with advanced capabilities designed to efficiently meet outdoor and indoor applications in a wide range of markets including city surveillance, critical infrastructure, financial institutions, airports and transportation, education, retail, commercial offices, and gaming establishments. All nine new Canon network cameras integrate advanced core components designed to deliver video with superb detail, vital color information and exceptional low-light performance. Those core components include advanced Genuine Canon lenses with High and Super High UD (Ultra-low Dispersion) lens elements and multilayer coatings, high sensitivity 1.3MP CMOS image sensors, and dual proprietary Canon DIGIC processors: the DIGIC DV III to help maximize image quality and the DIGIC NET II for simultaneous streaming of H.264 and M-JPEG video streams in multiple resolutions for versatile monitoring and recording (including monitoring on compatible smartphones and tablets).

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(CW1) Canon having Problems with Glass Supply?

Canon Rumor

Northlight Images reports a rumor suggesting that Canon’s…

glass supplies (more exotic types) are limiting the introduction of a whole load of new top end lenses. Canon has new manufacturing capacity, but optical glass making still takes a lot of time and is not just something you can just quickly ramp up

Sounds unreliable to me, and never I got any suggestion pointing in this direction. For me it’s CW1.

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Canon EF 11-24mm f/4L Review (outstanding image quality, Photography Blog)

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After a new set of 76 samples, Photography Blog posted their full review of the amazing Canon EF 11-24mm f/4L lens, the world’s widest rectilinear zoom. In the conclusion they write:

Image quality is outstanding. Chromatic aberrations are very well controlled, bokeh is pretty impressive despite the slow f/4 aperture and the wide-angle nature of the lens, and the Super Spectra coatings successfully prevent contrast loss attributable to flare. The only real optical issues are obvious vignetting throughout the zoom range (but particularly at 11mm), predictably obvious barrel distortion at the 11mm wide-angle focal length, and a slight lack of both centre and edge sharpness when shooting wide-open at f/4 at the 24mm focal length.

There have been only positive reviews about this $3,000, professional lens. The EF 11-24mm f/4L is now available at Amazon US | Adorama | DigitalRev | B&H Photo.

[via Photography Blog]