A converter lens includes three or more negative lenses and increases the focal length of an entire system, in which an average refractive index Ndave at the d-line (wavelength of 587.56 nm) of a material of all the negative lenses included in the converter lens is defined.

An accessory attachable to and detachable from an image pickup apparatus includes a memory configured to store first data having a first characteristic for correcting image data obtained by the image pickup apparatus, and second data having a second characteristic different from the first characteristic for correcting image data obtained by the image pickup apparatus, and a communication unit configured to transmit first information based on the first data and second information based on the second data to an external apparatus.

Provided are a camera system, a camera, a lens, an accessory, and an accessory detection method of a camera system capable of simply and quickly detect presence or absence of an attachment of the accessory and a type of the accessory. Data for accessory detection is transmitted from the lens to the camera. In a case where the accessory is attached between the lens and the camera, the accessory relays the data for accessory detection. At the time of relaying the data for accessory detection, the accessory adds own accessory information to update the data for accessory detection. The camera detects the presence or absence of the attachment of the accessory and the number of attachments of the accessory based on the received data for accessory detection. Further, in a case where the attachment is detected, the camera acquires information on the attached accessory.

A device adapter is used to mount a handheld device, such as a smartphone, to the binocular tube of a microscope, such as a slit lamp. The handheld device has a camera, a device surface on one side, and a camera lens at the one side. The adapter includes a body with an abutment surface, two side grippers and a lower gripper used to secure the device against the abutment surface of the body. The device adapter also includes an adapter assembly including a camera lens opening alignable with a handheld device camera lens so that an image entering the outer end of the ocular tube with integrated optics passes through the ocular tube, through the integrated optic, and through the camera lens opening for passage into the camera lens.

A device includes a housing with a recessed area and a raised peripheral section surrounding the recessed area, wherein the recessed area is recessed with respect to the raised peripheral section. A gripping mechanism is provided in the recessed area. The gripping mechanism is adjustable to hold portable electronic devices of a plurality of different sizes. A light source is provided in the raised peripheral section, to emit light from the raised peripheral section.

An apparatus including a camera optical element and a tactile indicator associated with the camera optical element for indicating a property of the camera optical element.

Light deflection prism for altering a field of view of a camera of a device comprising a surface with a camera aperture region defining an actual light entrance angular cone projecting from the surface. A method comprises disposing a first surface of a light deflection prism on the surface so as to overlap the angular cone; internally reflecting a central ray, entering the prism under a normal incidence angle through a second surface, at a third surface of the prism towards the first surface under a normal angle of incidence such that the central ray enters the prism at an angle of less than 90° relative to a normal of the device surface and such that a ray at one boundary of an effective light entrance angular cone defined as a result of the light reflection at the third surface is substantially parallel to the device surface.

Filter holder (10) having a tubular overall shape and made of an elastic material, an annular groove (40) being formed on the interior surface of the filter holder.

The accessory apparatus includes an accessory communicator providing a notification channel (RTS), a first data communication channel (DCL) and a second data communication channel (DCL). The accessory controller transmits, in a transmission request receiving state of receiving a transmission request from an image-capturing apparatus through the notification channel, accessory data to the image-capturing apparatus through the first data communication channel, and receives camera data transmitted through the second data communication channel from the image-capturing apparatus in response to receiving the accessory data. The accessory controller stops, in the transmission request receiving state and during transmission of the accessory data to the image-capturing apparatus, in response to becoming a non-transmission request receiving state, transmitting the accessory data to the image-capturing apparatus.

The accessory apparatus includes an accessory communicator providing a notification channel, a first data communication channel and a second data communication channel. The accessory controller transmits, in response to receiving a transmission request from an image-capturing apparatus through the notification channel, accessory data to the image-capturing apparatus through the first data communication channel and receives camera data transmitted from the image-capturing apparatus through the second data communication channel. The accessory controller has a function of detecting a camera communication error in the camera data and is configured to, when detecting the camera communication error, transmit accessory error information to the image-capturing apparatus and erase the accessory data stored in an accessory data buffer.