In cinematography, a focus puller or first assistant camera (1 AC) is the member of a film crew responsible for keeping the camera's focus right during a shoot. Often this requires pulling the focus with a follow focus device during the take, to compensate for camera or subject movement. Although literally it means writing in light, the term cinematography is generally understood as the art and process of recording visual images for the cinema (with a camera) and later developping those images in a laboratory. ... This article or section should include material from filming production roles Film crew and equipment on a location shoot. ... A camera is a device used to take pictures (usually photographs), either singly or in sequence, with or without sound, such as with video cameras. ... The word focus (pl. ... The word focus (pl. ... A follow focus is attached to a film or DV cameras manual servo lens and subsequently onto the body of the camera via a set of rods that are standardized in the film industry. ... This article needs cleanup. ...

To accurately focus on the subject, it's common to measure the distance (usually with a tape measure) between the camera and the subject being focused before the take. Specifically the measurement is from subject to film plane or CCD, most movie cameras have a little stud even with the film plane where the focus puller will attach his tape measure. Profesional 1st AC's have many tricks for pulling focus in difficult situations, such as when accurate measurement is impossible. Self-retracting pocket tape measure A tape measure or measuring tape is a ribbon of cloth, plastic, or metal with linear-measure markings, often in both imperial and metric units. ... A film plane is the area inside any camera where the individual frame of film is positioned during exposure. ... A charge-coupled device (CCD) is a sensor for recording images, consisting of an integrated circuit containing an array of linked, or coupled, capacitors. ... A film plane is the area inside any camera where the individual frame of film is positioned during exposure. ...

The 1st AC is also responsible for maintaining the camera including keeping the lens and film gate clean during filming. They are also responsible for placing filters in the matte box infront of the lense and for being aware of lens flares. The film gate is the square opening in the front of a motion picture camera where the film is exposed to light. ... Photograph of NASA lunar lander containing lens flare Lens flare typically manifests in images or views through optical systems as several starbursts, rings, or spheres arrayed in a sequence across the image or view. ...