sony hxr-nx70u

Focus

You can manually focus the camera using the manual ring on the front of the camera.

To do a manual focus, on the front left of the camera push the FOCUS button.

Then just above set the ZOOM/FOCUS/IRIS switch to FOCUS.

Switch determines what the focus ring will adjust on Sony NX70

You now can turn the manual ring to adjust the focus.

When the camera is set to manual focus, on the LCD screen will appear a hand icon with the letter F in the middle.

To return to automatic focus, push the FOCUS button again (the manual focus icon will disappear from the LCD screen).

Follow focus

The Sony NX70 is equipped with a follow focus features. To use the follow focus while in automatic mode, tap anywhere on the LCD screen where you want the camera to begin tracking the subject matter. The camera tries to look for areas of contrast, so tapping a blue sky or a plain wall usually doesn't work well. 

Follow focus feature on Sony NX70

For a few seconds after tapping a subject on the screen, a cancel button will appear to remove the follow focus. If the subject matter leaves the frame, this will also cancel the follow focus.