Manual Focussing

Two key terms that are often used when filming Manual Focus shots are:

Depth Of Field: Depth Of Field is the term used for the distance between the object/s that are closest and furthest away in the foreground and background of the shot.

Focus Pull: Focus Pull is the technique used that transfers the focus of the shot from one object to another.

Here is an example from an actual piece of  media:

During this sequence there is a large number of focus pulls, and manual focusing. It especially becomes clear at around 2:30 while Harry is looking at his mom and 2:40 when Niall looks at his Brother. I think this is an excellent example of how the technique is used and suits the video brilliantly.

Here Some Examples of Manual Focus Pulling 

Manual focussing is a technique used in film making, while the camera is rolling to focus and un-focus accepts of the frame and footage. This technique can be used often  to make the audience focus on a certain things in the frame.