Police Photography

Question 1

Purpose of crime/accident scene photography

Answer 1

• to provide a permanent visual record
• to show particular items of evidence and their relationship to the scene
• to make close up records of significant portions of the scene
• to refresh memory, substantiate testimony and clarify understanding

Question 2

Three criteria of photography as evidence

Answer 2

Accurate-“a fair and accurate representation of the scene as it appeared”
Authentic-not staged or recreated unless specifically indicated as being so, otherwise the scene is to be photographed as found
Relevant-the photo must pertain to an issue before the court, like any other evidence

Question 3

The portion of a scene that is seen through the camera lens. Angle of view is determined by the focal length of the lens used. Wide angle sees more, telephoto lens sees less. A “normal” lens views similar to human eye.

Answer 3

Angle of view

Question 4

The variable sized opening in the lens, used to control the amount of light allowed to pass on to the film. The lens opening is usually expressed in f-numbers.

Answer 4

Aperture

Question 5

A numerical rating of a film’s light sensitivity. Lower rated films are less sensitive to light and require more light for proper exposure. Lower rated films provide more detail. Allows greater enlargement without graininess

Answer 5

ASA/ISO

Question 6

Shooting a number of photos of the same subject, from the same viewpoint, at different levels of exposure to ensure at least one properly exposed print. Usually done by intentionally under exposing and overexposing around what is believed to be an optimal exposure.

Answer 6

Bracketing

Question 7

The range of sharp focus in a photograph. The distance between the nearest and farthest parts of the subject or scene that will appear acceptably sharp on the film.

Answer 7

Depth of field

Question 8

The distance, measured in millimeters, from the optical center of the lens to the film plane where objects at infinity are brought into sharp focus.

Answer 8

Focal length

Question 9

The shutter system of most SLRS. A pair of moving curtains or blades that opens to form a slit that moves directly in front of the film to allow an image to form.

Answer 9

Focal plane shutter

Question 10

The point at which light converges to form a sharp image. Achieved by adjusting the distance scale of the lens so that a selected part of the subject appears sharp.

Answer 10

Focus

Question 11

Numbers used to indicate the size of the lens opening that allows light to enter the camera and expose the film. The smaller the number the larger the opening and vice versa

Answer 11

F-Stops

Question 12

How to calculate f-stop

Answer 12

Dividing the focal length of the lens by the diameter of the lens opening. Best thought of as a fraction. F-2 is half the size of the lens’ focal length: 50mm lens on f-2, the aperture is 25mm wide.

Question 13

The measure of power of a flash unit.

Answer 13

Guide number.

Question 14

With a small light source, like a flash unit, it’s intensity is inversely proportional to the square of the distance from the light source: twice the distance, one quarter the light intensity.

Answer 14

Inverse square law

Question 15

The three factors influencing proper exposure are: film speed, aperture, shutter speed, the distance from flash to subjects becomes a fourth factor, if flash, rather than ambient light is used.

Answer 15

Exposure triangle

Question 16

One stop change of shutter speed or f-stop setting represents a halving or doubling of the light allowed to reach the film. Each doubling of exposure must be accompanied with a halving of exposure by the other setting.

Answer 16

Reciprocal exposure

Question 17

The number indicating the amount of time that light is allowed to reach the film in the camera. Designations are in fractions of a second: 30 is actually 1/30th of a second.

Answer 17

Shutter speed

Question 18

A camera in which the scene to be photographed is reflected by a mirror, onto a glass where it can be focused n composed. The scene is viewed through the same lens that takes the picture. When the picture is taken, the mirror swings out of the way allowing light to strike the film.

Answer 18

SLR: single lens reflex

Question 19

The shutter speed of a particular camera that ensures the entire film area is exposed when the flash unit fires.

Answer 19

Sync speed

Question 20

An inherent quality of lenses is that the area of sharpness for any subject extends one third in front of and two thirds behind the prime subject.

Answer 20

Zone focusing

Question 21

Selective focus-Width

Answer 21

The eye focuses on one object at a time. To eliminate distracting elements from the scene you must:
Come in closer to the subject, cutting out detail to the sides of primary subject
Use a longer focal length lens with a narrower angle of view
Use a zoom lens, which can also narrow the angle of view

Question 22

Selective Focus- Depth

Answer 22

The eye focuses on one object at a time. The camera can be set so that near, far and mid-distance objected are simultaneously in focus. By manipulating exposure settings, the photographer chooses how deep the area rendered in focus will be.

Question 23

Motion

Answer 23

The camera can create a blur using a relatively long shutter speed. The camera can capture an object as perceived by the eye. The camera can capture minute parts of a sequence occurring too fast for the eye to perceive.

Question 24

The normal lens

Answer 24

For 35mm SLR cameras, this is usually a 50 mm lens. Provides photo image close to how the eye originally perceived the scene. No distortion a between far and near objects.

Question 25

Wide angle lenses

Answer 25

Encompass a wider field of view than the normal lens. Magnify the apparent distance between the foreground and the background. Exaggerate the size of objects close to the lens.

Question 26

Telephoto lenses

Answer 26

Have a narrower field of view, than the normal lens. Compress the apparent distance between the foreground and background. Enlarge/magnify the size of distant objects: bring distant objects closer to camera/magnification power

Question 27

Focal length

Answer 27

The distance in mm between the film plane and the optical center of the lens when the lens is focused on the infinity

Question 28

7.5mm (fisheye)

Answer 28

180 degrees

Question 29

20mm

Answer 29

94 degrees

Question 30

28mm

Answer 30

75 degrees

Question 31

35mm

Answer 31

63 degrees

Question 32

50mm

Answer 32

47 degrees-approximates the human field of vision

Question 33

135mm

Answer 33

18 degrees

Question 34

500mm

Answer 34

5 degrees

Question 35

1000mm

Answer 35

2.5 degrees