Image-capturing apparatus, accessory apparatus and storage medium storing control program

An image-capturing system comprising:

• an image-capturing apparatus;
• and
• an accessory apparatus detachably attachable to the image capturing apparatus,
• the image capturing apparatus and the accessory apparatus respectively comprising:
• a camera communicator and an accessory communicator configured to provide three channels that are a notification channel used for providing a notice from the image-capturing apparatus to the accessory apparatus, a first data communication channel used for transmitting accessory data from the accessory apparatus to the image-capturing apparatus, and a second data communication channel used for transmitting camera data from the image-capturing apparatus to the accessory apparatus;
• and
• a camera controller and an accessory controller configured to control data communication therebetween,
• wherein:
• the accessory controller is configured to:
• transmit, during receiving a transmission request as the notice from the image-capturing apparatus through the notification channel, the accessory data in frame units to the image-capturing apparatus through the first data communication channel;
• and
• transmit the accessory data including a start bit indicating a start of each of frames of the accessory data, and
• the camera controller is configured to:
• in response to detecting the start bit included in each frame of the accessory data, transmit one frame of the camera data to the accessory controller through the second communication channel;
• and
• perform detection of the start bit regardless of whether or not during transmitting the camera data to the accessory apparatus.

An accessory apparatus detachably attachable to an image-capturing apparatus, the accessory apparatus comprising:

• an accessory communicator configured to provide, with the image-capturing apparatus, three channels that are a notification channel used for providing a notice from the image-capturing apparatus to the accessory apparatus, a first data communication channel used for transmitting accessory data from the accessory apparatus to the image-capturing apparatus, and a second data communication channel used for transmitting camera data from the image-capturing apparatus to the accessory apparatus;
• and
• an accessory controller configured to control data communication with the image-capturing apparatus through the accessory communicator,
• wherein the accessory controller is configured to transmit, to the image-capturing apparatus, the accessory data whose data length of one frame is longer than that of one frame of the camera data.

An image-capturing apparatus to which an accessory apparatus is detachably attachable, the image-capturing apparatus comprising:

• a camera communicator configured to provide, with the accessory apparatus, three channels that are a notification channel used for providing a notice from the image-capturing apparatus to the accessory apparatus, a first data communication channel used for transmitting accessory data from the accessory apparatus to the image-capturing apparatus, and a second data communication channel used for transmitting camera data from the image-capturing apparatus to the accessory apparatus;
• and
• a camera controller configured to control data communication with the accessory apparatus through the camera communicator,
• wherein the camera controller is configured to receive, from the accessory apparatus, the accessory data whose data length of one frame is longer than that of one frame of the camera data.