Canon RF-S3.9 mm F3.5 STM DUAL FISHEYE Instructions Manual page 15

5. Filters (Sold separately)
This lens has a rear filter holder at the rear.
It can take screw-in filters (φ30.5mm) or sheet filters (gelatin filters).
When using screw-in filters:
Filter Rear filter holder
1
Attach the filter (φ30.5mm) to
the rear filter holder mounting
thread.
Only one filter may be used.
z
Please note that some filters cannot be attached, depending on their thickness or shape.
z
If you force the filter on, you could damage the lens or filter.
Attachment position mark
Rear filter holder index
2
Match up the rear filter holder index and the
attachment position mark on the lens, and turn
the rear filter holder clockwise until it reaches
the stop position mark.
Removal is the reverse of attaching.
z
Stop position mark
Rear filter holder index
ENG-14