A control method of controlling an accessory apparatus detachably attachable to an image-capturing apparatus and 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 data transmission from the accessory apparatus to the image-capturing apparatus, and a second data communication channel used for data transmission from the image-capturing apparatus to the accessory apparatus, the control method comprising the steps of:
- causing the accessory apparatus to acquire, in response to receiving a transmission request as the notice from the image-capturing apparatus through the notification channel, a first time at which the transmission request is received;
- causing the accessory apparatus to acquire, in response to receiving a specific command through the second data communication channel, the accessory information corresponding to the first time or a second time acquired based on the first time;
- and
- causing the accessory apparatus to transmit the accessory information to the image-capturing apparatus through the first data communication channel.