The control knob of this extension ring can be used with focus gear of Canon EF 11-24mm f/4 USM (P.N.
19551) and Canon EF 16-35mm f/2.8L II USM (P.N. 19527). The control knob is set to be use with 19551 by default.
To use 19542, a larger cog (supplied) have to be installed. Please follow the instruction below for changing the cog of
the control knob.
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4
1.
Indentify of cogs.
For 19551
C1124-F
For 19542
C1635II-F
2.
Remove the cog by unscrewing the screw.
3.
Replace with the correct cog and install it
back to the shaft of the control knob by
tightening the screw.
