Power Focus (PF) Mode
Using the playback ring enables smooth focus change.
This is a useful feature for changing focus when shooting movies.
![](/library/CANON/CITS_TECH_SUPPORT/Camera/Lenses/EF%20400mm%20F2.8L%20IS%20II%20USM/PF1.png)
![](/library/CANON/CITS_TECH_SUPPORT/Camera/Lenses/EF%20400mm%20F2.8L%20IS%20II%20USM/PF2.png) |
![](/library/CANON/CITS_TECH_SUPPORT/Camera/Lenses/EF%20200-400mm%20f4L%20IS%20USM%20Extender%201.4x/1.png) |
With the focus preset switch set to OFF, set the focus mode switch to PF. |
![](/library/CANON/CITS_TECH_SUPPORT/Camera/Lenses/EF%20400mm%20F2.8L%20IS%20II%20USM/PF3.png) |
![](/library/CANON/CITS_TECH_SUPPORT/Camera/Lenses/EF%20200-400mm%20f4L%20IS%20USM%20Extender%201.4x/2.png) |
Rotate the playback ring to change the focus. |
When the playback ring is rotated in a certain direction, focus changes in the same direction as when the focusing ring is rotated.
You can make a 2-step change in focus shift speed depending on the angle that the playback ring is rotated to.