Canon RF-S3.9 mm F3.5 STM DUAL FISHEYE Instructions Manual page 11

Focusing/Control ring
The lens does not have a focus mode switch or
z
a focusing/control selector switch.
Delayed focus may occur if the focusing ring
z
(focusing/control ring) is quickly turned.
Adjust for any difference in focus between the
z
left and right lenses. For details, see 4. Checking/
Adjusting Left and Right Focus.
This lens does not support Servo AF. Before
z
movie recording, set the focus using One-Shot
AF or manual focus.
This lens' focusing/control ring is electronic.
z
It is possible to set cameras that support
z
electronic fulltime manual focusing to manual
focusing when the camera is in the operational
mode. However, the camera settings need to be
changed.
When AF operation is set to One-Shot AF,
z
manual focus is possible after autofocusing
has been completed by continuing to press the
shutter button halfway (electronic manual focus
function). However, the camera settings need to
be changed.
During movie mode, the AF speed will be slower
z
than in still image shooting mode.
Please refer to the camera's instructions for
details.
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