Better way then clone() to get a single frame

Hi all, Noob question: I'm creating a history of faces, and currently the only way i found to do that is to create a face.clone() (other methods just make a copy of the video and then i have lots of little video's on the side, and i need a still frame) of the face it found. Is there a less cpu intensive way to do that (maybe like cap >> frame) ? Thanks