Canon Patent: Electric Tilt-shift Lens Operation (take #2)

Here is another Canon patent for electric tilt-shift lens operation. The other one was published last week.

Canon patent application 2023-140195A (Japan, published 10/4/2023) discusses technology and methods for a tilt-shift lens with electronic controls.

From the patent literature:

An object of the present invention is to provide a control device that can establish a desired focus plane for a desired subject or object plane using a desired tilt effect in hand-held photography.

BACKGROUND ART

Conventionally, an optical system has been proposed that has a tilt effect that tilts a focusing surface so that an object surface tilted with respect to the optical axis of an imaging optical system is brought into good focus over the entire surface. . Patent Document 1 discloses a surveillance camera system that includes a lens unit and a camera device that have a tilt effect, determines the amount of tilt for each specific area set as a shooting range, and focuses on a subject using a desired focus plane.

However , in the camera system disclosed in Patent Document 1, when the position of the camera device changes, it is necessary to set the tilt amount for each specific area. Therefore, when hand-held photography is performed using the camera system of Patent Document 1, there is a possibility that the desired tilt effect may not be obtained.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a control device that can establish a desired focus plane for a desired subject or object plane using a desired tilt effect during hand-held photography .

Means for Solving the Problems

A control device as one aspect of the present invention includes an imaging device including an imaging device, and at least one optical member for tilting a focusing surface with respect to an imaging surface of the imaging device. A control device used in a camera system having a lens device having an optical system including an acquisition unit that acquires information about a designated subject, and a subject for constructing a focus plane based on information about the designated subject. and a control unit that acquires information regarding the position of the.

The lens barrel 2 has an optical system, a zoom operation ring 6, a guide barrel 7, a cam barrel 8, a lens-side CPU 9, and an aperture mechanism 11 . The optical system includes a first group lens 21, a second group lens 22, a third group lens 23, a fourth group lens 24, a fifth group lens 25, a sixth group lens 26, a seventh group lens 27, an eighth group lens 28, a ninth group lens 29, and A 10-group lens 30 is provided. In this embodiment, by moving at least one lens (optical member) included in the optical system, at least a tilt effect that tilts the focus plane with respect to the imaging surface of the image sensor 1106 and a shift effect that moves the imaging range are achieved. You can get one. Each lens is held by a lens barrel with a cam follower. The cam follower engages with a straight groove parallel to the optical axis O provided on the guide tube 7 and a cam groove inclined with respect to the optical axis O provided on the cam tube 8. When the zoom operation ring 6 rotates, the cam cylinder 8 rotates, and the positional relationship of each lens in the Z-axis direction changes. As a result, the focal length of the lens barrel 2 changes. The focal length of the lens barrel 2 can be detected by a zoom position detection section (not shown) that detects the amount of rotation of the zoom operation ring 6. The lens-side CPU 009 changes the aperture diameter of the optical system by controlling the aperture mechanism 11. In this embodiment, by moving the sixth group lens 26 and the eighth group lens 28 in a direction perpendicular to the optical axis O, a tilt effect or a shift effect can be obtained. Specifically, by moving the sixth group lens 26 and the eighth group lens 28 in opposite directions, a tilt effect can be obtained, and by moving them in the same direction, a shift effect can be obtained. The lens-side CPU 9 controls the sixth lens group 26 via a drive section using a signal from a detection section (not shown) that detects the amount of movement of the sixth lens group 26 . Further, the lens side CPU 9 controls the 8th group lens 28 via a drive section using a signal from a detection section (not shown) that detects the amount of movement of the 8th group lens 28. The drive unit that moves the sixth group lens 26 and the eighth group lens 28 is, for example, a stepping motor or a voice coil motor (VCM). Note that it is also possible to obtain a tilt effect by tilting (rotating) the lens.

In the camera system 1 of this embodiment, if three points to be focused are specified, the subject plane 500 is constructed as described above, and photography can be performed with the desired subject in focus . However, for example, in so-called “reverse tilt photography (miniature photography)” in which cityscapes and people are photographed by blurring the top and bottom of the photograph, the photographer may decide where to focus and what to blur. In that case, the vector OB is defined by the spatial coordinate points O and B designated by the photographer. The photographer instructs the surface 501 to rotate by an angle θctrl using the vector OB as the rotation axis. For example, the photographer can instruct the surface 501 to rotate by an angle θctrl by performing a touch operation of sliding a finger back and forth on the display unit 1108. Further, instructions may be given using line-of-sight input using the EVF, rotating operation of the aperture operation ring 20, and buttons or dials (not shown). Alternatively, it may be determined automatically according to the set shooting mode of the camera 3. The photographer aligns the object surface 500 with the surface 501 that provides the desired degree of blur while maintaining the desired object (spatial coordinate points O, B) in focus.

More Canon patents are listed here.

[via asobinet]