Canon patent for EF 17-35mm f/4-5.6 IS STM lens

canon patent

Here is a patent application that could make it into production, more sooner than later.

Canon patent application in Japan 2017-16156 describes the optical formula for an EF 17-35mm f/4-5.6 IS STM lens. Since Canon started to build non-L, STM lenses for their full-frame cameras, it was to expect that this popular focal length would follow. We usually point to the fact that most patent never make it into production. This one may be different.

  • focal distance: 17.50  25.12  34.09
  • f numbers: 4.00 4.85   5.88
  • half field angle (degree): 51.03  40.73  32.40
  • image height: 21.64  21.64  21.64
  • length of the lens: 130.88 128.52 134.05
  • BF: 37.60  49.75  64.06

Here are two more patents (1 and 2) that could likely go into production.

Source

Canon patent for stacked sensor design (AF and image data off the sensor)

canon patentCanon patent application US20170366776 describes several stacked sensor designs.

The patent focuses on separating auto-focus and image data pipelines from the chip on the image sensor. Such a design has several advantages: less bandwidth to transfer data from the sensor, which leads to more speed and reduced power consumption (hence also less heat).

The patent abstract:

An imaging element having a layered structure including a first chip having a pixel portion in which pixels for photoelectrically converting an optical image of an object and generating a pixel signal are arranged two-dimensionally and a second chip in which a drive means of the pixel portion is arranged, and having a first output path to output the pixel signals of at least a first pixel group in the pixel portion and a second output path to output the pixel signals of a second pixel group, comprises the a conversion means for converting the pixel signals of the first and second output paths into digital signals and a control information generation means for generating control information of a photographing operation of the object by using the digital signal converted by the conversion means, wherein at least a part of the conversion means is arranged in the first chip.

Please note that patent applications do not mean a company will implement the described technology any time soon. Indeed, most patents never make it into production. An example of a Canon patent describing a technology that might be featured on a future Canon DSLR can be seen here, another one here.

Canon patent to improve raw file burst rate through lossy compression

canon patentCanon patent application US20170359471 describes an algorithm to improve raw file writing performance during burst shoots. This is an example of patent that likely will be found on a future Canon DSLR.

The patent abstract:

An imaging apparatus according to the present invention includes: an imaging unit configured to generate RAW image data by imaging; a generation unit configured to generate record RAW image data from the RAW image data; and a recording unit configured to record in a storage unit the record RAW image data, wherein the generation unit generates the record RAW image data by performing Lossy compression on the RAW image data in a case where consecutive shooting is performed, and generates the record RAW image data by performing Lossless compression on the RAW image data in a case where single shooting or bracket photographing is performed.

The interesting aspect is: raw files are compressed and saved lossy only when burst shooting, during normal operation raw files will be saved lossless. The patent literature states the algorithm:

  • record RAW image data is generated by performing lossy compression on the RAW image data in a case where consecutive shooting is performed, and
  • record RAW image data is generated by performing lossless compression on the RAW image data in a case where single shooting or bracket photographing is performed.

I am not sure if I want lossy compressed raw files on my camera. What about you?

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.