Canon patent for 400mm f/5.6 mirror lens (aka catadioptric lens)

mirror lens

Canon Japan filed a patent for a 400mm f/5.6 mirror lens. A mirror lens (or reflex or catadioptric lens).

I guess not everyone is informed on what a mirror lens is. So, here is what Wikipedia says:

Various types of catadioptric systems are also used in camera lenses known alternatively as catadioptric lenses (CATs), reflex lenses, or mirror lenses. These lenses use some form of the cassegrain design which greatly reduces the physical length of the optical assembly, partly by folding the optical path, but mostly through the telephoto effect of the convex secondary mirror which multiplies the focal length many times (up to 4 to 5 times). This creates lenses with focal lengths from 250 mm up to and beyond 1000 mm that are much shorter and compact than their long-focus or telephoto counterparts. Moreover, chromatic aberration, a major problem with long refractive lenses, and off-axis aberration, a major problem with reflective telescopes, is almost completely eliminated by the catadioptric system, making the image they produce suitable to fill the large focal plane of a camera.

Catadioptric lenses do, however, have several drawbacks. The fact that they have a central obstruction means they cannot use an adjustable diaphragm to control light transmission. This means the lens’s F-numbervalue is fixed to the overall designed focal ratio of the optical system (the diameter of the primary mirror divided into the focal length). Exposure is usually adjusted by the placement of neutral density filters on the front or rear of the lens. Their modulation transfer function shows low contrast at low spatial frequencies. Finally, their most salient characteristic is the annular shape of defocused areas of the image, giving a doughnut-shaped ‘iris blur’ or bokeh, caused by the shape of the entrance pupil.

Patent JP-A-2017-219642 discusses such a catadioptric lens.

  • Focal length: 400 mm
  • F No: 5.6
  • 2 ω: 1.96
  • Image height: 13.66mm
  • Back focus: 33.07mm
  • Lens length: 247.73mm

Source

Canon patent shows a better way to review multiple shots

canon patentHere is a Canon patent (United States Patent 9843731) which might show how you may review multiple shots on your Canon camera in the future.

Multiple shots are sequences of photos produced by continuous shooting or bracketed shooting. Usually, sequence of pictures obtained by such “shooting instructions” (that’s patent language) are reviewed in a sequential form (although with some variations). Canon want’s to offer a better experience.

According to the patent literature, there a two ways photos can be displayed for review:

(a) sequentially displaying each image of the generated set of images in a single image display form on a display unit, wherein in the single image display form each image of the generated set of images is switched from one to another, and then, (b) displaying the generated set of images in a multi-image display form, wherein in the multi-image display form each image of the generated set of images are displayed on a same screen of the display unit without displaying any live view image and any image shot in response to any shooting instruction other than the single shooting instruction, wherein each image of the generated set of images displayed in the single image display form is displayed in a larger size on the display unit than each image of the generated set of images displayed in the multi-image display form.

If I got it right, and having a look to the patent illustrations, this means that you’ll see a bunch of photo on your camera display, that you can navigate this photo set though a touch sensitive interface, and the magnify any photo from the set. Have a look at the images below.

Any idea/suggestion/correction is welcome.

Canon patent to miniaturise the aperture mechanism of a lens (new pancake lenses?)

canon patent
Drawing from the patent literature

Canon patent regarding how to miniaturise the aperture mechanism of a lens. Specifically, the patent seems to refer to lenses where miniaturisation plays an important role. Such lenses may be made for special application, but it could also mean a pancake lens.

Let’s see patent JP2017-187730A’s abstract:

PROBLEM TO BE SOLVED: To provide a light quantity adjusting device capable of achieving downsizing of a device while obtaining a good aperture stop shape.
A diaphragm driving section disposed outside of the base plate, a pair of linearly advancing blades linearly advancing and retracting with respect to the opening section, 107, and a plurality of oscillating blades 105, 109, 106, 108 which oscillate diagonally from both sides in the moving direction of the pair of rectilinearly moving blades in the moving direction toward the center of the opening to obtain a good aperture opening shape while trying to downsize the device.

I hope this Canon patent points to new, compact lenses, preferably pancake lenses for Canon APS-C and EOS M systems.

Yet another hybrid viewfinder patent by Canon

hybrid viewfinderCanon’s labs are actively working on hybrid viewfinder technology. This is not the first patent referring to this very technology.

The new patent is patent JP2017-146322A, The patent’s abstract says:

PROBLEM TO BE SOLVED: To solve problems of an increased size, a complicated mechanism and the like of a camera employing a viewfinder device allowing switching between an optical viewfinder (OVF) and an electronic viewfinder (EVF).
SOLUTION: A main mirror that directs a subject image from a lens to a viewfinder and performs reciprocating revolving movement between a subject observation position and an image pick-up position in which an image pick-up device receives light of the subject image from the lens is configured to have both a display function to display, e.g., an image picked up by the image pick-up device and a mirror function to direct the subject image to the viewfinder, thereby realizing: an OVF mode in which the subject image on a reticle is observed with the viewfinder using the mirror function of the main mirror; and an EVF mode in which the main mirror is in an up state and a live view image of the subject is displayed by the display function of the main mirror and observed with the viewfinder.

If you like “patentish language”, you may want to dive into the patent’s claims:

[Claim 1] A main mirror (4) which carries out the both-way rotational movement of the object image from an object observation position and a lens (2) which leads an object image from a lens (2) to a finder between image pickup positions which carry out light reception to an image sensor (17),
It constitutes so that it may have a display function (6) which displays a taken image of an image sensor (17), and a function of a mirror which leads an object image to a finder,
OVF mode in which an object image on a reticle (11) is observed with a finder using a mirror function (5) of a main mirror (4),
A finder device of a camera having the EVF mode which changes a main mirror (4) into a rise state, displays a live view image of an object by a display function (6) of a main mirror (4), and it observes with a finder.
[Claim 2] A finder device of the camera according to claim 1 using the aforementioned display function as a transparent display device (6) which used an EL element.
[Claim 3] A finder device of the camera according to claim 1, wherein a mirror function of the aforementioned main mirror (4) will comprise a modulated light mirror which changes reflectance and will be in a transmission state in EVF mode with impressed electromotive force.
[Claim 4] It is a main mirror (104) which carries out the both-way rotational movement of the object image from an object observation position and a lens (2) which leads an object image from a lens (2) to a finder between image pickup positions which carry out light reception to an image sensor (17),
When it evacuates to an image pickup position, it has a gobo (109) for plugging up an opening on the back surface side of the main mirror (104),
A display part (106) which displays a taken image of an image sensor (17) on a surface on the main mirror (104) side of the gobo (109) is provided,
OVF mode in which lead an object image from a lens (2) to a finder by a main mirror (104), and it observes an object,
A finder device of a camera having the EVF mode which displays a live view image of an object on a display part (106) provided to the aforementioned gobo (109) in the state of the rise of a main mirror (104), and it observes with a finder.
[Claim 5] A finder device of the camera according to claim 4, wherein the aforementioned main mirror (104) will comprise a modulated light mirror which changes reflectance and will be in a transmission state in EVF mode with impressed electromotive force.
[Claim 6] A finder device of the camera according to any one of claims 1 to 5 switching the aforementioned OVF mode and the aforementioned EVF mode, and observing an object.

Source

Canon patent for illuminated rear buttons on camera body

illuminated rear buttons
A drawing from the patent application

Interesting patent that already started speculations.

Patent JP2017-147019A (which can be seen here in its entirety) refers to illuminated buttons on the rear of a Canon camera body (a DSLR, typically).

This is something Nikon already has: illuminated rear buttons. This lead someone to the speculation that the EOS 7D Mark III may have these buttons. While possible, there are no hints it will. So far we have to deal with wishful thinking and not with a rumor.

The patent’s abstract:

To provide a light emission button mechanism that enables a letter or character on the surface of a button to emit light uniformly with a simple configuration without providing any dedicated separate member for light guiding and light shielding, and can prevent light leakage to the inside and outside of the device.
SOLUTION: A light emission button mechanism includes an operation portion having a light guide portion that transmits light, an exterior cover having a hole through which the operation portion is inserted, a switch unit having a movable unit which is elastically deformed by pressing the operation unit, and a contact unit which is to operate by further pressing the operation unit, light emitting mans which is arranged in a substantially sealed space formed by the operation unit and the switch unit and causes the light guide portion to emit light, and a conductive pattern connected to the light emitting means and formed in the switch unit, and at least the conductive pattern formed in the movable portion out of the conductive patterns is not linear.

Source

Nikon working on full-frame mirrorless camera, patents suggest (and where is Canon’s?)

mirrorless
Patent for 50mm f/0.9 lens

While the Canon community is eagerly waiting to know more (or at least something really reliable) about the long rumored (and much wished) Canon full-frame mirrorless camera (all rumors), we learn that Nikon is also working on such a camera.

Two Nikon patents for 50mm f/0.9 and 35mm f/1.2 lenses specifically designed to be featured on a full-frame mirrorless camera have been spotted. It is a hint that Nikon has such a camera on a blueprint at least.

We found similar patents filed by Canon in the past (1 | 2), and even a patent for an EF/EF-S adapter for a full-frame mirrorless camera. I just wish we would know something more. The latest rumor regarding Canon’s full-frame mirrorless camera is here, I sum it up:

  • Different sources and sites were reporting that early prototypes exist, at least to be tested inside Canon’s labs. This intel came in 2016 and early 2017.
  • Canon is possibly working on a full-frame mirrorless camera with EF mount. There have been rumors saying that Canon is delaying this camera because of issues in implementing the EF mount. There is a lot of talk about this. If Canon manages to engineer a full-frame mirrorless camera with EF mount, thus allowing us to use our beloved EF lenses on a smaller and hopefully performing body, it will be a winner. Imagine what you could do with a MILC that goes along with your EF lenses. There is serious a chance we may see this.
  • The latest bit of info I got suggests Canon will announce a full-frame mirrorless camera with a sensor having a resolution of 36-38MP.
  • A possible announcement date is around Photokina 2018, which happens in September.
  • And for all those 4K fans out there: we have been told that, yes!, most likely it will feature 4K video.

Do you think we will see a Canon full-frame mirrorless camera in 2018?

  • Yes (56%, 195 Votes)
  • No (44%, 156 Votes)

Total Voters: 351

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