Attaching the Flash Unit 
Hold down the release buttons and attach the flash unit to the front of the lens.
Make sure the flash unit is securely attached.
The flash unit can be rotated.
To detach the flash unit, follow the above procedure in reverse.
1 Hold down the release button and attach the mount ring to the front of the lens.
Position the release button toward the top. Make sure the mount ring is securely attached.
2 Attach flash heads A and B to flash head mounts.
Push it in until it clicks in place.
To detach the flash heads, press the release lever (p.6).
To EF100mm f/2.8L Macro IS USM Users
Macro Lite Adapter 67 (optional) is required. Screw on the adapter onto the lens filter thread, then attach the flash unit.
To EF180mm f/3.5L Macro USM Users
Macro Lite Adapter 72C (optional) is required. Screw on the adapter onto the lens filter thread, then attach the flash unit.
To rotate the mount ring, be sure to first hold down the release button. If the Macro Lite Adapter 72C screwed onto the EF180mm f/3.5L Macro USM lens filter thread becomes stuck and cannot be unscrewed, without pressing the release button, turn the ring against the lens in the direction you would to detach the Adapter.
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