[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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[Patent] Canon’s New EF 600mm f/4 and EF 400mm f/2.8 Lenses

600mm f/4
400mm f/2.8

Japanese site egami (Google translated) spotted two new Canon patents. The patents refer to the EF 600mm f/4 and the EF 400mm f/2.8 lenses. The lenses will have reduced size and weight. The 600mm will have 15 elements in 9 groups, the 400mm 14 elements in 9 groups (more specs below). Performance charts:

Performance Chart 600mm f/4
Performance Chart 400mm f/2.8

More specifications (machine-translated)…:

  • Patent Publication No. 2012-88427
    • 2012.5.10 Release Date
    • 2010.10.18 filing date
  • Example 1
    • Focal length f = 585.00mm
    • Fno 4.12
    • Image height 21.64mm
    • Length 468.50mm lens
    • BF 90.78mm
    • 15 sheets of 9 group lens configuration
    • One aspherical surface a
    • 2 UD glass sheet
    • One fluorite
    • A plane diffraction
  • Example 2
    • Focal length f = 391.86mm
    • Fno 2.88
    • Image height 21.64mm
    • Length 367.51mm lens
    • BF 50.01mm
    • Lens Construction 14 elements in 9 groups sheet
    • 2 2 aspherical surface
    • 1 UD glass sheet
    • One fluorite
    • A plane diffraction
  • Group 3 consists of positive and negative positive
  • Inner Focus (group 2)
  • Strengthen the refractive power of the front lens group, and to shorten the overall length, the sensitivity is increased, it is difficult to manufacture and assembly
  • The number of lens group at the end of the super-telephoto lens is determined by the balance of the total length and chromatic aberration
    • And shorten the length and reconcile, the correction of chromatic aberration, the number will increase
      • It is important to the length of each degree
    • Weight of the first lens group, 70% to 9 on the whole
      • Canon patents is reduced to three the first group
      • Aspherical and one eye in group 1 group, field curvature correction, the distortion
      • Diffractive optical element and the second two groups in the first group, the chromatic aberration correction
[egami via CR]

Canon patent to keep your EXIF data private (on the web)

Japanese site Egami spotted a Canon patent to obscure EXIF-information and protect your privacy. This is a particularly sensible issue if considered with regard to social networks like Facebook. EXIF data contains lots of information you may not want to deliver to the world, as geographic location, dates and time. These information allow everyone to know where you have been and when you were there (and which camera you used :-) ). Two kinds of EXIF outputs are discussed: high accuracy and low accuracy. High accuracy EXIF data is the usual data. The “low precision” EXIF data is obtained by obscuring some of the information. For instance “if the information is numeric, the digit of the lower [digits is] cut off“, and in case of alphanumeric data some of the characters will be hidden. Another way is used to obscure dates and times. As the image below shows, an exact date-time information is made fuzzy. Look at the time: from 9:45:13 it becomes a range (between 9:00 and 10:00)

A similar operation is done with GPS data. The geographic information is made more vague. In the picture below, the exact position is transformed in somewhere inside the dotted lines.

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Canon Patent for Improved Auto-Focusing Method

Canon secured a patent (EP20120151498) for an auto-focusing algorithm (and unit) to speed up auto-focusing operations of a digital DSLR while tracking moving objects (at least this is what I understood by reading the patent). Is this the next generation of Canon’s AF systems?

A focus control method is provided that performs focus control by sensing a plurality of images of an object while moving a position of a focusing lens and determining in-focus positions in auto focusing areas located at a plurality of positions. The focus control method calculates an in-focus position of the focusing lens based on the focusing lens position at the time of reading an image signal of each of the auto focusing areas and a degree of focused state of each of the auto focusing area that is based on the image signal of each of the auto focusing areas.

The patent aims at resolving issues caused by the rolling shutter method used to control an electronic shutter. This works as follows:

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Liquid Lens Patent by Canon (and video)

Ever heard about liquid lenses? It may be the next big thing in optical engineering. Basically, liquid lenses work by applying an electric voltage to an electrolytic solution (that’s the liquid) in order to curve its surface (called meniscus). You probably are already thinking: Hey, that means no moving parts! And you are right. Liquid lenses have a series of advantages over traditional lenses. Beside not having moving parts (and thus less mechanical parts), they  respond quicker to electrical signals, they do not have a motor (you thought that USM was the big thing? Think again) and they are naturally much more silent. Just one quick note: Not having a motor means they need less electrical power, and that means the battery charge will last longer. There is a 10 minutes video at the end of the post that explains the technology. Fun to watch and good examples. Ok, let’s see the patent (it was very tiring to read :-)).

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