This Canon patent application might point to the next generation of Canon’s Defocus Smoothing technology.

Canon patent application 2022124678 (Japan) discusses technology and optical formulas to obtain Defocus Smoothing by the mean of electrochromic elements (EC). Defocus Smoothing is Canon’s technology to improve bokeh (see short video below for an explanation).

From the patent literature:

BACKGROUND ART

An electrochromic (hereinafter sometimes referred to as “EC”) element is an element having a pair of electrodes and an EC layer disposed between the electrodes. It is an optical element that adjusts the hue and amount of light in the visible light band by applying a voltage between them to oxidize or reduce the compounds in the EC layer.

EC elements have already been applied to products such as variable transmittance windows for aircraft and anti-glare mirrors for automobiles. Attempts have been made to apply it to The apodization filter is an optical element that smoothes the outline of a blurred image, and has a transmittance distribution in which the transmittance decreases with increasing distance from the optical axis.

In the conventional EC device described above, a desirable transmittance distribution is achieved by defining the resistance range of the electrodes, but the setting of the constituent requirements was not sufficient. That is, the transmittance distribution of the solution-type EC element depends on the resistance ratio between the electrode resistance and the solution resistance per unit width. , depending on the resistivity of the electrochromic layer (solution). Therefore, it was necessary to define these in order to achieve a desirable transmittance distribution.

An object of the present invention is to provide an EC element capable of realizing a suitable transmittance distribution in a solution-type EC element in which power is supplied from the outer periphery of the dimming area, and furthermore, a suitable transmittance by following the aperture diameter of the mechanical aperture of the lens. It is an object of the present invention to provide an EC device capable of forming an index distribution. Another object of the present invention is to provide a lens unit and an image pickup apparatus having excellent optical characteristics using such an EC element.

To me it appears this might be the next generation of the Defocus Smoothing technology.

More patents are listed here.

Very interesting Canon patent application: a set of RF mount lenses with electronically controlled Defocus Smoothing (DS).

Defocus Smoothing is a technology Canon first introduced with the RF 85mm f/1.2L DS lens (see here for our coverage). The featured Canon patent might suggest more DS lenses are on their way.

Canon patent application 2020-199390 (Japan) discusses optical formulas and methods for three prime lenses with DS:

• 135mm f/2
• 400mm f/4
• 50mm f/2.5

From the patent literature:

PROBLEM TO BE SOLVED: To provide an optical device capable of sufficiently adjusting the clarity of the outline of a blur even if the aperture diameter of a diaphragm is greatly changed.

BACKGROUND ART: Conventionally, an image formed by an optical device may be required to include a blur with a smooth outline, or may include a blur with a clear outline. May be required.

Patent Document 1 discloses an optical device capable of smoothing or clarifying the outline of blur by providing an optical element capable of reversibly switching the distribution of transmittance. The clarity of the outline of the blur is required to be sufficiently adjustable even when the aperture diameter of the diaphragm is greatly changed.

However, the optical device disclosed in Patent Document 1 is insufficient to meet the above-mentioned requirements because the clarity of the outline of the blur can be sufficiently adjusted only in the vicinity of the opening of the aperture.
Therefore, an object of the present invention is to provide an optical device capable of sufficiently adjusting the clarity of the outline of a blur even if the aperture diameter of the diaphragm is greatly changed. In various optical systems such as photographic and video lenses, not only the characteristics of the image plane but also the image quality of the out-of-focus portion, that is, the quality of blur may be emphasized.

In general, there are cases where a smooth blur that melts without a clear outline is desired, and there are cases where a blur with a clear outline is desired. As a method of changing the contour of the blur, for example, a method of inserting an apodization filter whose transmittance decreases as the distance from the optical axis increases is known.

As a result, the transmittance distribution of the apodization filter is superimposed on the blurred image, and smooth blurring such that the contour melts can be realized. However, when the apodization filter is inserted, the outline of the blur is always smooth in the vicinity of the opening of the aperture, so that it becomes difficult to clarify the outline of the blur according to the request.

Further, when the apodization filter is inserted, the amount of transmitted light in the optical system is reduced, so that the demerit of inserting the apodization filter becomes greater in the shooting scene where almost no blurring occurs in the screen.
Therefore, there is also known a method of switching the apodization effect on and off by using an optical element capable of reversibly controlling the distribution of the transmittance, that is, adjusting the clarity of the outline of the blur according to a request.

Example 1

• Focal length: 133.05
• F value: 2.06
• Half angle of view: 9.24
• Image height: 21.64
• Overall length: 170.39
• Back focus: 45.96

Example 2

• Focal length: 399.84
• F value: 4.00
• Half angle of view: 3.10
• Image height: 21.64
• Overall length: 298.46
• Back focus: 145.16

Example 3

• Focal length: 49.00
• F value: 2.50
• Half angle of view: 23.82
• Image height: 21.64
• Overall length: 68.15
• Back focus: 11.00

The following, short video tells what Defocus Smoothing is:

[via asobinet]

A new Canon patent application. Three fast primes are discussed, all seem to have Defocus Smoothing on board.

Defocus Smoothing is an optical technology introduced first on the RF 85mm f/1.2 DS. Canon patent application 2021-196547 (Japan) discusses optical formulas for the following lenses:

• 50mm F1.4
• 135mm F1.4
• 24mm F1.4

All three lenses have Defocus Smoothing. From the patent literature:

PROBLEM TO BE SOLVED: To provide an optical system having high wavelength uniformity in a pupil surface.

As an optical element used in an optical device, an ND (Neutral Density) filter for adjusting the amount of transmitted light is known. In particular, in order to improve the variation in sharpness of the contour of the out-of-focus image (blurred image) (to obtain the apodization effect), a gradation type ND filter (GND filter, apodization filter) having different transmittance for each region is used. Be done. Patent Document 1 describes a GND filter in which an apodization effect is obtained by using a film whose thickness changes for each region.

However, in Patent Document 1, the uniformity (wavelength uniformity) of the transmittance distribution on the pupil surface with respect to the wavelength when the GND filter is applied to the optical system is not considered.

The optical system as one aspect of the present invention is an optical system having an optical element including a first region in which the transmittance changes in the radial direction, and the optical element is an optical axis perpendicular to the radial direction. A substrate arranged along the direction and a first layer are provided, the maximum incident angle of an axial marginal ray with respect to an optical surface included in the optical system is θm, and the extinction coefficient of the first layer at a wavelength of 550 nm.

More Canon patent applications are listed here. Some particularly interesting patent applications we think might get into production are these:

• Automatic shutter silencing based on subject and distance
• A bunch of prime lenses for the RF mount
• An improved Electronic Viewfinder
• Patent application for RF 50mm F1.4 and an RF 35mm f/1.4 lenses
• A zoom lens that might be for an EOS R with APS-C sensor
• A smaller IBIS unit.
• A cooling adapter for the RF mount (R5 overheating?)
• A bunch of macro lenses for the RF mount.
• A 8mm f/4 circular fisheye lens for the Canon EOS R system
• A battery grip that works with differently siszed cameras
• A 100-400mm f/5.5-7.1 lens for APS-C cameras. EOS M or DSLR?
• RF 17-70mm lens for EOS R system
• IBIS coming to the EOS M and PowerShot lineup?
• Patent Application: mirrorless camera with large display and virtual control wheel
• Patent Application: IBIS and Lens IS Working Together
• Patent application for high speed mirror movement and control
• Patent application for an RF 14-28mm f/2 lens
• Patent application for an RF 50mm f/1.8 lens
• Patent application for a smart lens cap
• Patent application for celestial auto-focus
• Patent application describing a Pop-Up Flash With LED
• Patent application describing the optical formula for a RF 70-300mm F/4-5.6 IS lens for EOS R systems
• Patent application describing how to improve burst rate by compressing raw files
• Patent application describing a new way to review photos from a sequential shot
• Patent application that describes technology to improve wireless communication while reducing power consumption
• Patent application to spot and reduce moire artefacts in image data
• Patent application for weather sealed lens adapter
• Patent application for AI powered predictive camera control system
• Patent application for 18-55mm kit lens with LCD display
• Patent application to reduce noise in image files

[via asobinet.com]