Depth of field: the area between the nearest and the farthest point in front of a lens in which an actor or object can move and stay in focus – dependent on such factors as the speed and focal length of the lens, the f-stop and the amount of light illuminating the action.
Exposure: the quantity of light passing trough the lens and on to the film over a given time, producing a latent image - perhaps the DP’s most important tool in defining the look of a film. For dramatic reasons, the DP may choose to use a degree of under or overexposure to create an atmospheric sense of darkness or brightness.
f-stop/t- stop: units of measurements indicating the degree of opening of the lens diaphragm determining how much light passes trough the camera aperture. (t-stops are more accurate). If any factors (such as changing light or variation in the speed of the camera motor) make the exposure unstable while filming, the f-stop may have to be altered manually.
Flaring: an effect created when the lens is pointed at a strong directional light source. Although regarded as a technical mistake, flaring is part of the modern cinematographer’s vocabulary, which can be used to evoke a sense of immediacy.
Focal length: the distance from the optical centre of the lens to the point just behind the lens where the image is in sharp focus, while the focus is set to infinity. Long focal lengths bring distant objects up close; short length push distant objects, further away, and give a much wider angle. Because different focal lengths affect the viewer’s sense of perspectives in different ways, choice of focal lens is a key factor in determining how best to render the dramatic action of a scene.
Prime: lens of fixed focal length.
Zoom: A lens of variable focal length, so that the magnification of the subject of a shot can be altered during filming. This allows an alteration in the sense of perspective between the subject and the background (unlike the tracking shot).