Chapter 6: Lenses

Question 1

aperture

Answer 1

iris opening of a lens

Question 2

auto-focus

Answer 2

automated feature whereby the camera focuses on what it senses to be the target object

Question 3

calibrate

Answer 3

to preset a zoom lens to remain in focus throughout the zoom

Question 4

compression

Answer 4

the crowding effect achieved by a narrow angle lens wherein object proportions and relative distances seem shallower

Question 5

depth of field

Answer 5

the area in which all objects, located at different distances from the camera, appear in focus. Depth of field depends on the focal length of the lens, its f-stop and the distance between the object and the camera

Question 6

digital zooming

Answer 6

simulated zoom that crops the center portion of an image and electronically enlarges it. digital zooms lose picture resolution

Question 7

fast lens

Answer 7

a lens that permits a relatively great amount of light to pass through at its maximum aperture. can be used in low-light conditions

Question 8

field of view

Answer 8

the portion of a scene visible through a particular lens, its vista. expressed in abbreviations, such as CU for closeup

Question 9

focal length

Answer 9

the distance from the optical center of the lens to the front surface of the cameras imaging device at which the image appears in focus with the lens set at infinity.

Question 10

focus

Answer 10

a picture is in focus when it appears sharp and clear onscreen.

Question 11

f-stop

Answer 11

the calibration on the lens indicating the aperture, or iris opening. The larger the f-stop number the smaller the aperture. The smaller the f-stop number, the larger the aperture

Question 12

iris

Answer 12

adjustable lens opening that controls the amount of light passing through the lens. Also called diaphragm and lens diaphragm

Question 13

macro position

Answer 13

a lens setting that allows it to be focused at very close distances from an object. used for close-ups of small objects

Question 14

minimum object distance (MOD)

Answer 14

how close the camera can get to an object and still focus on it

Question 15

narrow angle lens

Answer 15

gives a close up view of an event relatively far away from the camera. aka long focal length and telephoto lens

Question 16

normal lens

Answer 16

a lens or zoom position with a focal length that approximates the spatial relationships of normal vision

Question 17

rack focus

Answer 17

to change focus from one object or person closer to the camera to one father away or vice versa

Question 18

range extender

Answer 18

an optical attachment to the zooms lens that extends its focal length

Question 19

selective focus

Answer 19

emphasizing an object in a shallow depth of field through focus while keeping its foreground and or background out of focus

Question 20

servo zoom control

Answer 20

zoom control that activates motor driven mechanisms

Question 21

slow lens

Answer 21

a lens that permits a relatively small amount of light to pass through at its maximum aperture. used in well lighted areas

Question 22

wide-angle lens

Answer 22

a short focal length lens that provides a broad vista of a scene

Question 23

z axis

Answer 23

an imaginary line representing an extension of the lens from the camera to the horizon. the depth dimension

Question 24

zoom lens

Answer 24

a variable focal length lens. it can gradually change from a wide shot to a close up and vice versa in one continuous move

Question 25

zoom range

Answer 25

the degree to which the focal length can be changed from a wide shot to a close up during a zoom.