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]

 

This came as a surprise. Could this mean Canon is working on a new version of the Powershot G1X? looks like.

Japanese blog Egami (translated) spotted a patent for two lenses with a 4/3 ratio. A 14-28mm f/1.4-2.4 and a 12-28mm f/2-3.2. I don't know what to think about that. The machine translated text is difficult to understand. If someone here can help with the interpretation, he or she is welcome. Any Japanese reader willing to help? :-) Quoting Egami:

Canon 28mm F1.8-2.8 is fourteen-28mm, 12- F2-3.2 ,14-28mm F1.4-2.4 of the patent is pending. 4/3 ” imaging element of becoming a zoom lens equivalent to 24-56mm. 4/3 corresponds to, or the 28-56mm, equivalent size 35mm ” imaging element while using, Myu4 / 3 lens without correspond to and if integrated, can realize the camera is so superior balance of performance, size.

• Patent Publication No. 2012-226042
  • Release Date 2012.11.15
  • Filing date 2011.4.18
• Example 1
  • Zoom ratio 2.37
  • 33.60 – – 28.74mm f = 14.20 focal length
  • Fno = 1.80 -. 3.30 – 2.93
  • Half angle of view ω = 37.13 – 17.74 – 20.51deg.
  • Image height 10.75mm
  • 77.74 – – 75.24mm 77.26 overall length of the lens
  • BF 1.46mm
  • 11 sheets in 10 groups lens configuration
  • Three four-sided aspherical
• Example 3
  • Zoom ratio 2.72
  • 33.60 – – 28.53mm f = 12.36 focal length
  • Fno = 2.06 -. 3.60 – 3.26
  • Half angle of view ω = 41.01 – 17.74 – 20.65deg.
  • Image height 10.75mm
  • 82.29 – – 79.22mm 82.03 overall length of the lens
  • BF 1.21mm
  • Eight 8 groups lens configuration
  • Four aspherical surface 7
• Example 4
  • Zoom ratio 2.37
  • 33.60 – – 28.74mm f = 14.20 focal length
  • Fno = 1.40 -. 2.71 – 2.39
  • Half angle of view ω = 37.13 – 17.74 – 20.51deg.
  • Image height 10.75mm
  • 80.53 – – 77.94mm 79.63 overall length of the lens
  • BF 1.51mm
  • 10 sheets of 9 groups lens configuration
  • Three four-sided aspherical

[via Egami]

 

Hopefully this leads to quicker hybrid AF. Canon filed a patent that aims at improving the speed of hybrid (phase and contrast detection) AF systems, particularly when tracking subjects. The patent’s abstract:

A camera to which a lens unit is exchangeably attached includes a phase difference detection type focus detection unit, a contrast detection type focus detection unit, and a processor configured to acquire correction information used to correct a shift amount between a focus detecting light flux and an image-pickup light flux from the image pickup lens. The contrast detection type focus detection unit performs scanning in a single direction from a focus position detected by the phase difference detection type focus detection unit, the single direction being set based on the correction information.

The patent tackles the following technical problem:

Since the [contrast detection focus method] has an excellent focus detection precision but requires a long time for focusing, the [contrast detection focus method] cannot be applied when an allowable time period required for the focus detection is short, in particular, in following a moving body or at the consecutive shooting time.

This is done in the following way:

A camera according to the present invention is a camera to which a lens unit is exchangeably attached. The lens unit includes an image pickup lens configured to form an object image, and is compatible with a first focus detection unit configured to provide a focus detection by detecting a phase difference between a pair of object images formed by utilizing a first pupil splitting unit. The camera includes a second focus detection unit configured to provide a focus detection by detecting a phase difference between a pair of object images formed by utilizing a second pupil splitting unit different from the first pupil splitting unit, a third focus detection unit configured to provide a focus detection by detecting a peak position of a contrast of the object image by performing scanning that changes a distance between an image pickup device and a focus position formed by the image pickup lens, and an acquisition unit configured to acquire correction information used to correct a shift amount between a focus detecting light flux and an image-pickup light flux from the image pickup lens. The third focus detection unit performs the scanning in a single direction from a focus position detected by the second focus detection unit, the single direction being set based on the correction information.

Good to know that Canon is working hard on a better hybrid Af system. :-)

[via freepatentsonline]

I reported about two similar patents filed by Canon in the past (here and here). Now Canon files another patent for phase detection Auto-Focus, explicitly referring to phase-detection AF for a camera with “removable lenses”.

The present invention has been made in view of the above-described problems, and provides an image- pickup apparatus in which a focus detecting pixel is arranged in a part of an image sensor to perform focus detection based on the phase difference detection method. With this arrangement, it is possible to reduce the frequency of lens driving upon focusing while preventing a hunting phenomenon upon focusing.

The image-pickup apparatus according to a first aspect of the present invention capable of mounting a removable lens unit with an image-pickup optical system including a focus lens thereon,

comprises: an image sensor in which an image-pickup pixel to receive a light beam passed through an exit pupil of the image-pickup optical system and a focus detecting pixel to receive a light beam passed through the exit pupil, partially shielded, of the image-pickup optical system are arrayed; focus detection means for detecting a shift amount of the focus lens from a focus position based on a phase difference in an output signal from the focus detecting pixel; and acquisition means for acquiring ray vignetting information of the image-pickup optical system, wherein, when a position detection resolution of the focus lens is lower than a drive resolution of the focus lens, the focus detection means detects the shift amount of the focus lens from the focus position using the ray vignetting information in a predetermined position of the focus lens specified based on information from the lens unit.

Could this be the patent for a new method to get phase-detection AF? Maybe it is for Canon’s next, pro-oriented mirrorless camera.

[via freepatentsonline]

Egami (translated) spotted another patent filed by Canon. This time it is for a 14mm f/2.8 lens with improved coating (tubular coating):

It seems it is possible to realize a low-refractive-index low reflectivity by the structure below the diffraction limit, even without the uneven surface of the coating. 14mm F2.8 is what I want you to adopt all means patent coating of the lens as the front lens is large, yet is protruding.

• Patent Publication No. 2012-159723
  • 2012.8.23 Release Date
  • 2011.2.1 filing date
• Example 1
  • F = 14.3mm focal length
  • Fno. = 2.89
  • Half angle ω = 56.6 °
  • 14 images in 10 groups lens configuration
• Existing coating roughness
  • In daily use, dirt or dust may adhere, could not wipe, sex or bad Mentenasu productivity and manufacturing process
• Canon patent
  • (Coating applied to one surface of a lens) thin film layer
  • Having a plurality of tubular spaces are arranged parallel to the tube
  • Maximum opening diameter of the tubular space below 400nm
  • The inorganic oxide materials (silica, titania)

[via Egami]