Canon EOS R3 Advanced User's Manual page 28

(1) Self-timer lamp/AF-assist beam
(2) Shutter button
(3) Multi-function button 2 (M-Fn 2)
(4) Depth-of-field preview button
(5) Grip
(6) < > Vertical-grip Multi-function button
(7) < > Vertical-grip Main dial
(8) Vertical-grip shutter button
(9) RF lens mount index
(10) Lens mount
(11) Lens lock pin
(12) Lens release button
(13) Shutter curtain/Image sensor
(14) Remote control terminal
(15) Contacts
(16) Vertical-grip depth-of-field preview button
(17) Vertical-grip Multi-function button 2 (M-Fn 2)
(18) Tripod socket
(19) Serial number (body number)
(20) Accessory positioning hole
(21) Body cap
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