A finder includes, in order from an object side to an eye point side, an objective optical system that forms an intermediate image, and an ocular optical system that is provided for observation of the intermediate image. The intermediate image is positioned on the optical path between the objective optical system and the ocular optical system. The finder includes a plurality of reflecting surfaces for forming an erect image, and each of the objective optical system and the ocular optical system has at least one of the plurality of reflecting surfaces. The finder satisfies a conditional expression: 2<fo/fe<8 regarding a focal length fo of the objective optical system and a focal length fe of the ocular optical system.

An optical system and a method for adjusting diopter are provided. The optical system includes an eyepiece (10), a half mirror (20), a display screen (30), a first motor (40) coupling with the display screen (30), an image sensor (50), and an image analysis system (60) coupling with the display screen (30), the first motor (40), and the image sensor (50). The first motor (40) controls the display screen (30) to move back and forth along the first optical axis (70). The image sensor (50) converts reflected light signals into fundus images. The image analysis system (60) controls the first motor (40) to adjust a distance between the display screen (30) and the half mirror (20) according to the fundus images.

There is provided a camera of which operability is good regardless of the brightness of the surrounding environment. The brightness of the surrounding environment is detected by a brightness detection unit provided in a camera. The contents of settings of the camera are displayed on a sub-display 18 in a situation in which the surrounding environment is bright. The contents of settings of the camera and an image representing the set state of a shutter speed dial 33 are displayed on the sub-display 18 in a case in which the surrounding environment is dark.

There is provided a camera of which operability is good regardless of the brightness of the surrounding environment. The brightness of the surrounding environment is detected by a brightness detection unit provided in a camera. The contents of settings of the camera are displayed on a sub-display 18 in a situation in which the surrounding environment is bright. The contents of settings of the camera and an image representing the set state of a shutter speed dial 33 are displayed on the sub-display 18 in a case in which the surrounding environment is dark.

A laser-based speed gun includes a camera module and a folded optical system including an objective lens and an eyepiece lens. The folded optical system includes first and second image redirecting elements for redirecting an image pathway from the objective lens to the eyepiece lens adjacent the camera module.

A laser-based speed gun includes a camera module and a folded optical system including an objective lens and an eyepiece lens. The folded optical system includes first and second image redirecting elements for redirecting an image pathway from the objective lens to the eyepiece lens adjacent the camera module.

A reflective truncated ball imaging system includes: a reflective truncated ball element having a first surface, a second surface and a third surface for reflecting incident light beams from an object having a width of X entering into the first surface, from the second surface towards the third surface to exit the third surface and form an image of the object with a width Y; a focusing lens for focusing the reflected light beams exiting the third surface; and a sensor or view finder for sensing or viewing the light beams focused by the focusing lens.

A reflective truncated ball imaging system includes: a reflective truncated ball element having a first surface, a second surface and a third surface for reflecting incident light beams from an object having a width of X entering into the first surface, from the second surface towards the third surface to exit the third surface and form an image of the object with a width Y; a focusing lens for focusing the reflected light beams exiting the third surface; and a sensor or view finder for sensing or viewing the light beams focused by the focusing lens.

There is provided an image pickup apparatus including: a main body provided with an image pickup section; a viewfinder having a main body part and a movable part, the viewfinder being capable of performing state transition in which the movable part moves in a first direction with respect to the main body part, to reach a usage state; and a control section configured to perform processing based on the state transition.

A driving apparatus which is capable of smoothly moving a follower by a cam portion, and realizes the stopper structure of the follower by a small number of components without the size increased. The driving apparatus comprises an up cam gear having an up radial cam and an up thrust cam, and a down cam gear unit having a down radial cam and a down thrust cam. The up cam gear and the down cam gear unit mesh with each other in a vicinity of a region in which a lift amount of the up radial cam with respect to the follower increases. In a vicinity of a position at which the up cam gear and the down cam gear unit mesh with each other, a lift amount of the up thrust cam is larger than a lift amount of the down thrust cam in the thrust direction.