Power Focus (PF) Mode
Using the playback ring enables smooth focus change.
This is a useful feature for changing focus when shooting movies.
*1
![](/library/CANON/CITS_TECH_SUPPORT/Camera/Lenses/EF%20400mm%20F4%20DO%20IS%20II%20USM/PF1.png)
![](/library/CANON/CITS_TECH_SUPPORT/Camera/Lenses/EF%20400mm%20F4%20DO%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%20F4%20DO%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.
*1 Power focus (PF) will work while a Live View image is displayed on the camera or when shooting movies for the following cameras:
EOS-1D X, EOS 5D Mark III, EOS 6D, EOS 70D, EOS REBEL T5i/700D, SL1/100D, T4i/650D, T5/1200D.
EOS M2
*2 and EOS M when used together with Mount Adapter EF-EOS M.
*2 Not available in certain countries and regions.