Cinema Ch 10 Terms
Horizontal dimension
x-axis
Vertical dimension
y-axis
Depth dimension
z-axis. illusion created by the composition of the frame. Wide angle tend to exaggerate depth
1/3-2/3 rule
2/3 of the depth range along the z-axis is behind the focus point and 1/3 is in front.
Focal plane (film plane)
A lens gathers incoming light and focuses it on the film plane. Face plate of the CCD chip
Lens speed
Ability of a lens to gather light.
Zooming in
Adjusting the optical center away from the focal plane and therefore increasing the magnification power of the lens (telephoto)
Zooming out
Adjusting the optical center back toward the focal plane, causing the image to become more wide angle.
Focus point
Aka. plane of critical focus. Precise distance in front of the camera, from the focal plane which will be in sharp focus.
Aperature
All light gathered by the lens must pass through the aperture before it is registered on film plane or imaging device.
Auto focus
Camera setting which favors objects in the center of the frame, and tends to shift focus in the middle of a shot when anything moves across the foreground of the frame.
Fast lens
Can open up to allow more light
Pulling focus
Change the plane of critical focus during a take, when the camera is running. Common practice
Aperature ring
Controls a slender disk, a diaphragm, inside the lens called the iris, which is made up of flat matte black metal blades.
Focal length
Determines the degree of magnification or de-magnification of the scene being shot. Determined by the distance between the optical center of the lens and the focal plane. Usually measured in millimeters
Stop
Each number on the f-stop scale. One stop has the effect of doubling or halving the amount of light allowed to pass.
Opening up
Expanding the aperture (smaller numbers)
T-stops
F-stops that have been adjusted to take into account the amount of light that is lost, dissipated or absorbed by that particular lens. Simply more accurate f-stops
Neutral density
Filters to block light
Presetting focus
First zoom all the way into the subject you want to have in focus, adjust the focus, and now zoom out and find your initial frame
Face plate
Focal plane where light is focused. front of the CCD chip
Focus
Generally defined as when a point of light reflecting off the subject is registered as a point of light on the focal plane.
Barrel
Holds the lens elements parallel to each other in a light-tight housing. Aka. Lens housing
Angle of view
How much of the scene the lens takes in horizontally and vertically
Prime lenses
Lenses that have one fixed focal length. Very common film production. Simple design allows them to be made with few glass lens elements, which means there is less chance for loss of light.
Witness mark
Line etched into a nonmovable part of the lens barrel
Telephoto Lens
Long lenses. Enlarge the size of the image and narrow the angle of view.
Manual mode
Manually adjusting focus.
Normal Lens
Medium lenses. Approximates the same perspective and image size that the human eye would see if one were to stand in the same spot as the camera
Zoom lenses (variable focal length lenses)
Offer a continuos range of focal lengths in one lens housing. Constructed with movable lens elements. Can offer a wide range of focal lengths in one lens
Focus ring
On a lens, brings a subject into focus by very precisely moving the front element of the lens forward and backward in relation to the focal plane
Slow lens
Opens up slower to gather light
Focus puller
Person who does the actual adjustments to the focus ring.
Setting marks
Place precise markers on the ground for the actor to hit during the course of their movement.
Rack focus
Shifting the plane of critical focus between two static objects along the z-axis
Wide angle Lens
Short lenses, and shorter focal lengths. Reduce the size of the image and broaden the angle of view.
Electronic shutter control
Reduce the light entering the camera
Closing down (stopping down)
Reducing the size of the aperture (bigger numbers)
Lens elements
Series of polished glass sections
F-stop scale
Size of the aperture opening calibrated. Etched into the aperture ring
Follow focus
Subject is moving along the z-axis either closer to or further away from the camera
Circle of confusion
The measurement of acceptable diameter, which creates the appearance of focus
Optical center
The point at which the image flips
Depth of field
range of apparent focus along the z-axis.