POLICE PHOTOGRAPHY A. DEFINITION OF TERMS: 1. Photography = Derived from the Greek word “Phos” or “Photos” which means “light” and “Grapho” means “Writing” or “Graphia” meaning “to Draw”. Sir John F. W. Herschel coined the word photography when he first wrote a letter to Henry Fox Talbot. = Is the art and science of reproducing image by means of light through some sensitized material with the aid of a camera, Lens and its accessories and the chemical process required in order to produced a photograph. 2. Forensic = Derived from the Latin word “Forum” which means “a market place” where people gathered for public discussion. = When used in conjunction with other science it connotes a relationship to the administration of justice. It is sometimes used interchangeably with the word legal. 3. Police Photography = Is the application of the principles of photography is relation to the police work and in the administration of justice. 4. Photograph = Is the mechanical and chemical result of Photography. Picture and photograph are not the same for a picture is a generic term is refers to all kinds of formed image while a photograph is an image that can only be a product of photography. B. USES OF PHOTOGRAPHY 1. Personal Identification = Personal Identification is considered to be the first application of photography is police work. Alphonse Bertillion was the first police who utilized photography in police work as a supplementary identification in his Anthropometry system. 2. For Communication = Photograph is considered to be one of the most universal methods of communication considering that no other language can be known universally than photograph. 3. For Record Purposes = Considered to be the utmost used of photography in police work. Different Views in photographing a. General View = taking an over-all view of the scene of the crime. It shows direction and location of the crime scene. b. Medium View = Is the taking of the photograph of the scene of the crime by dividing it into section. This view will best view the nature of the crime. c. Close-up View = Is the taking of individual photograph of the evidence at the scene of the crime. It is design to show the details of the crime. d. Extreme Close-up View = Commonly designed in laboratory photographing using some magnification such as Photomacrography and photomicrography. 4. For Preservation = Crime scene and other physical evidence requires photograph for preservation purposes. Crime scene cannot be retain as is for a long period of time but through photograph the initial condition of the scene of the crime can be preserved properly. 5. For Discovering and Proving = Photography can extend human vision in discovering and proving things such as: a. The use of Magnification Photomicrography = Taking a magnified photograph of small object through attaching a camera to the ocular of a compound microscope so as to show a minute details of the physical evidence. Photomacrogaphy = Taking a magnified (enlarged) photograph of small object by attaching an extended tube lens (macro lens) to the camera. Microphotography = is the process of reducing into a small strips of film a scenario. It is first used in filmmaking. Macrophotography = used synonymously with photomacrogaphy. Telephotography = Is the process of taking photograph of a far object with the aid of a long focus and Telephoto lens. b. Used of Artificial Light such as X-ray, Ultra-violet and Infra-red rays to show something which may not be visible with the aid of human eye alone. 6. For Court Exhibits = Almost all evidence presented in court before formally be accepted requires that they satisfy the basic requirements for admissibility which is relevancy and competency. A question of relevancy is usually proved by proving the origin of the evidence and its relation to the case and this is usually supplemented by photograph of the evidence giving reference as to where it came from. Evidence presented in court once accepted became known as Exhibit. Either Exhibit 1,2,3 etc. for the defense or Exhibit A, B, C etc for the prosecution. 7. Crime Prevention = with the used of video camera (hidden camera) and other advanced photographic equipment crimes are being detected more easily and even to the extent of preventing them from initially occurring. 8. Police Training = Modern facilities are now being used as instructional material not only in police training as well as in other agencies. 9. Reproducing and Copying = With the use of photography any number of reproduction of the evidence can be made those giving unlimited opportunity for its examination and even allow other experts or person to examine the specimen without compromising the original. C. ESSENTIALS OF PHOTOGRAPHY 1. Light = is an electromagnetic energy that travels in a form of a wave with the speed of 186, 000 miles per second. 2. Camera = a light tight box designed to block unwanted or unnecessary light from reaching the sensitized material. 3. Lens = is the light gathering mechanism of the camera that collect the reflected light coming from the object to form the image. 4. Sensitized material = composed of a highly sensitized chemical compound which is capable of being transformed into an image through the action of light and with some chemical processes. ( Film and Photo Paper). 5. Chemical Process = is the process necessary for reducing silver halides into a form so as a latent image and a positive image be made resulting to what we called Photograph. D. THEORIES OF LIGHT 1. The WAVE Theory (Huygens) = It is the theory that was transcribed from the motion of the water that if we observe a piece of log floating in the ocean and with the force of the air would naturally will make the log move up and down. 2. Corpuscular theory (Newton) = this later opposed the wave theory stating that light has its effect by the motion of very small particles such as electrons. 3. Modified Wave theory (Maxwell and hertz) = Based on electromagnetics. All these theories are still considered to be of little lacking that law enforcement need not to be very focus on this but rather go along with the accepted conclusion that light is a form of energy, which is electromagnetic in form. E. LIGHT: ITS NATURE, CHARACTERISTICS, SOURCES AND CLASSIFICATION Light is defined as an electromagnetic energy with the speed of 186,00 miles per second. Its wave travel is said to be characterized in certain extent based on velocity, wavelength and frequency of the number of vibration of the wave per second. Light wavelength is the distance measured between two (2) successive crest or through of wave and it is expressed in either Millimicron (nanometer) or Angstrom. Millimicron is the units of light wavelength which is equivalent to one-millionth part of a millimeter which the Angstrom is relatively smaller for it has an equivalent measurement of ten (10) millionth part of a millimeter. Once light hits a certain medium, its action can be characterized as either: Reflected, Transmitted or Absorbed (RAT). Reflected once the light hits a mirror and it bounce back. Transmitted when the light hits a transparent glass which would allow the light to pass through its medium and Absorbed when the light hits a dark colored object and prevents it from either bouncing or passing through. Isaac Newton in 1666 proved that the light which men see as white light is actually a mixture of all colors of the spectrum. This is produced when we allow light to hit a glass prism (Sharp Edge of the Glass). A rainbow array will then be shown with colors red, orange, yellow, green, blue and violet colors (from top to bottom). The visible light is also said of have a wavelength of between 400-700 millimicron or nanometer. 1. Types of Light Lights can largely be classified into visible and invisible light. a. Visible Light = Is the type of light that produces different sensation when reach the human eye. It is the type of light, which is capable of exciting the retina of the human eye. b. Invisible Light = lights in which their wavelength are either too short or too long to excite the retina of the human eye i.e. X-ray, Ultrat-violet and Infra-red lights. 2. Photographic Rays a. X-ray =Light with the wavelength between .01 to 30 millimicrons. It is produced by passing an electric current through a special type of vacuum tube. It was incidentally discovered by Conrad Welhelm Roentgen. This type of light works in the principle of shadow photography. b. Ultra-violet ray (Before the violet) = Radiation having a wavelength of 30 to 400 nanometers designed to photograph fingerprints in multi colored background, documents that are altered, decipherment of erase writing and developing invisible writing. It is commercially known as “black Light”. c. Visible Light = It refers to the type of radiation having a wavelength of 400 to 700 millimicrons designed for ordinary photographing purposes. d. Infra-red (Beyond the Red) = Considered as the photographic rays with the longest wavelength ranging from 700 to 1000 millimicrons. It is designed to take photograph of over-written documents, obliterated writing, and charred documents or for black out photography. It is sometimes referred to as heat rays). 3. Light Source A. Natural Light= are those light which come to existence without the intervention of man e.i. Sunlight, moonlight and starlight. 1. Bright Sunlight = object in an open space casts a deep and uniform shadow and the object appears glossy. 2. Hazy Sunlight = object in an open space casts a transparent or bluish shadow. This is due to thin clouds that cover the sun. 3. Dull Sunlight = object in an open space cast no shadow due to thick clouds covering the sun. Daylight may still be classified as: open space bright sunlight, under shade bright sunlight, hazy sunlight, cloudy sunlight and cloudy dull sunlight. These conditions and their colors affect the appearance of the object being photograph. Factors such as atmospheric vapor, atmospheric dust and quality of the reflected light coming and not coming from the source should likewise be considered. B. Artificial Light = otherwise known as man-made light e.g. fluorescent bulb, incandescent bulb and photoflood lamp. 1. Continuous radiation Photoflood lamp= is likewise known as Reflectorized light or Spot light. It is a light with a reflector at the back which focus the light to the object the common wattages of this lamp is 500 watts. Flourescent Lamp = are tube lamps in which the walls are coated with fluorescent powders with both ends is mounted with a holder that serves as the reflector. This is commonly used by everybody more than it is used in photographing. Incandescent bulb = are bulb with a wire filament connecting two wires which sustain the electrical charge that produces the light. Everybody likewise commonly uses this although it is more expensive in terms of electrical consumptions. Infra-red Lamp Ultra-violet Lamp 2. Short Duration type Flash bulb = are chemical lamps, as it generate lights by the rapid combination of metal in oxygen. The bulb can be used only once as the bulb is busted when fired electrically. There are thin filaments inside the bulb with two electrical contacts. When the current flows through the filament, it becomes incandescent and ignites the explosive primer that ignites the aluminum foil that burns, giving flash of tense light. Electronic Flash = produces light by an instantaneous electrical in charges between two electrodes in a gas filled glass bulbs. The electrical energy for the discharge is kept in capacitor or condenser. It usually ranges from 1/300 second and 1/5000 second, and because of this, subject in fast motion can be arrested or stopped in the photographs. 4. SENSITIZED MATERIAL = It refers to the film and photographic paper that basically composed of emulsion containing Silver Halides suspended in gelatin and coated on a transparent or reflective support. Parts of the Sensitized Material 1. Emulsion = is that part of the film or photographic paper which contains the silver grains which is the one sensitive to light. In a colored film this emulsion surface can be composed of three layers (Blue, Green and Red) with filters intervening. 2. Anti Halation Backing = is the one designed to hold back the light and prevents halation. 3. Base = Support the emulsion I. Types of Film A. According to Use 1. Black and White Film = usually represented by a prefix or a suffix “Pan” or “Ortho” and generally used in black and white photography. Examples are Ortholith film, Tri X-Pan and Pan X-plus. 2. Colored Film = can be divided into two: the Negative type and the reversal type of colored film. The former is usually having names ending in color while the word chrome represents the latter. e.g. Blue sensitive film, Ultra-violet film, Infra-red film, Orthochromatic film and Panchromatic film. B. According to Spectral Sensitivity Spectral sensitivity = is the responsiveness of the film emulsion to the different wavelength of the light course. 1. Blue – Sensitive film = sensitive to U.V. light and Blue Color. 2. Orthochromatic Film = Sensitive to U.V. Light up to the green. ( popular in the marker as KODALITH FILM) 3. Panchromatic film = Sensitive to U.V. Light up to red (sensitive to all colors of the visible light) 3.1. Process Panchromatic film = permit short exposures under average lighting condition and has the advantage of the grain structure. 3.2. Grain Panchromatic film 3.3. High Speed Panchromatic film designed originally for photographing object under adverse lighting condition. 4. Infra-red Film = Sensitive to all colors and to infra-red light. FILM SPEED (Emulsion Speed) This refers to the degree of sensitivity of the film to light. 1. ASA (American Standards Association) = this is expressed in arithmetic value system. The bigger the number the more sensitive the film is. ASA 10, 20 , 30 , 40,50, 100, 200, 400, 800, 1000 2. DIN ( Deutche Industre Normen) = expressed in Logarithmic value system. Used in the same principle as the ASA. Din 12, 15, 18, 21, 24, 27, 30, 33 etc. 3. ISO (International Standard Organization) expressed as combination of ASA and DIN rating. II. Photographic Paper It is that sensitized material that will record the visible image in the final development and become the photograph. Types of Photographic Papers A. According to Emulsion Used (Silver halides content) 1. Silver Chloride paper = used for contact printing, the size of the positive print is the same as the size of the negative used. Sensitivity to light is low and give blue-black tones when properly developed. 2. Silver Bromide paper = used projection, printing and enlarging process. This is one of the most ideal photo paper used for police photography. Will give a black tone when properly developed. 3. Silver Chlorobromide paper = used both for projection and contact printing. Slow emulsion. 4. Variable contract paper = combines the contrast range in one paper it uses a special chlorobromide emulsion that produces varying contrast responses upon exposure to different colors of light. B. According to Physical Characteristics b.1. Weight 1. Light weight = designed for high flexibility and when paper thickness is not of consideration. Intended for purposes, which involves folding. 2. Single Weight = papers used for small prints or which are need to be mounted on solid and fine details necessary in the production. Used in ordinary photographic purposes. 3. Double weight = generally used for large prints because they stand up under rough treatment. b.2. Surface Texture a. Glossy paper =designed for fine details and brillant image formation. b. Semi-mate paper = obscure the fine details c. Rough papers = used for large prints or where breath rather than detail is necessary. b.3. Color a. White = better used in police photography. b. Cream = preferred for pictorial effect, portraits, landscape or when warmth effect is desired. c. Buff papers = prepare for tone prints C. According to Contrast (grade) 1. Velox No. 0 = used for printing extremely contrast negative or extremely exposed film. 2. Velox No. 1 = used for high contrast negative (over exposed film) 3. Velox No. 2 = used for normal exposed film 4. Velox No. 3 = used for negative with weak contrast (under exposed) 5. Velox No. 4 = used to provide sufficient contrast to compensate for very thin or weak negatives. It is useful imprinting which high contrast is desired. 6. Velox No. 5 = for flat negative that are unprintable. 5. CAMERA Is a light tight box with light gathering device and a means of blocking unwanted or unnecessary light from reaching the sensitized material. Basically, camera can produce image with its four-(4) basic parts such as light tight box, lens, and shutter, Holder of sensitized material. Essential Parts of a Camera 1. Light Tight Box – a box designed to keep light out and serve as a frame to hold other parts. 2. Lens – designed to collect or to focus the reflected light from an object to form an image on the film. 3. Shutter – designed to control the time during which the light reaches the film 4. Holder of the sensitized material – located at the opposite side of the lens designed to hold firmly the sensitized material to prevent the formation of the multiple or blurred image 5. View finder – designed to determine the field of view of the camera or the extent of the coverage of the given lens OTHER PARTS OF A CAMERA A. Viewing System Is that part of the camera which provides the means of showing to the photographer the entire scene coverage that can be recorded in the sensitized material. B. Film Advancer (film advance lever or knob) =designed to transfer the exposed film to the other side or to the take up spool and the unexposed film will be the opposite side of the lens for another exposure. C. Shutter speed = is that part of the camera which regulates the time exposure of the film thus, affecting the amount of light reaching the sensitized material. It is usually expressed in a fraction of a second. 1/1 1/2 1/4 1/8 1/15 1/30 1/60 1/125 1/250 1/500 etc. The speed number in the left is always two times powerful in terms of light gathering than that of the right number Using a fast shutter speed the photographer can stop or “freeze” the action of a person provided that necessary adjustment on the lens opening be made in order to maintain normal exposure. D. Lens Aperture = the ratio between the diameter of the whole lens in relation to the focal length of the lens. It is the light gathering power of the lens. Otherwise known as lens opening or relative aperture and it is expressed in F-number. f 2.8 f-4 f-5.6 f-8 f-11 f-16 The lower the f-number, the bigger the lens opening and the bigger the lens opening the greater the volume of air that will passed through the lends and reach the sensitized material. If the objective of a photographer is obtain the widest possible coverage of the lens in which objects are all sharp, It will be advisable to used a smaller lens opening. E. Focusing = is that mechanism of a camera designed to control the degree of sharpness of the object to be photograph. It is usually obtained by estimating the distance from the camera and that of the object that will make a sharp or clear image. Types of focusing device: 1. Range finder (Either coincidence or split image type) Coincidence otherwise known as superimposed image focusing. In this type of focusing a single object will appeared double once the object is not in focus, but moving the focusing adjustment this double image will coincide or superimposed to form a single object. Split Image focusing on the other hand will show an image in split or two parts once the object in not in focus once the two parts of the image has been united then the object is already focused 2. Ground Glass This is observed from the viewing system of the camera, once the object is not in focused the object will be viewed to be blurred and will turn sharp and clear once adjusted. 3. Scale Bed Estimating the distance of the object and adjusting the camera control based on his estimation do this. TYPES OF THE CAMERA 1. View Finder Type – it is considered as the smallest and the simplest type of camera 2. Single Lens Reflex Camera – it is a type of camera best suited for police work due to its interchangeability of the lens 3. Twin Lens Reflex Camera – A type of camera with dual lens, one for focusing and the other for forming the image. 4. View or Press type – is considered the biggest and expensive type of camera, used for movie making 5. LENS = It is the image-forming device of the lens that actually has a greater effect on the quality of the image to be formed. = a medium or system which converge or diverge light rays passing through it to form an image. = Can be a glass or transparent material, which permit light to pass through and change the direction of light. Daniel Barbaro = first to introduce the use of lens in the camera. CLASSIFICATION OF LENSES 1. According to the type of image to be produced a. Positive or Convex Lens (Converging Lens) Characterized by the fact that it is thicker at the center and thinner at the side which is capable of bending the light together and forms the image inversely. b. Negative or Concave Lens (diverging Lens) Characterized by the fact that it is thinner at the center and thicker at the side and forms the virtual image on the same side of the lens. 2. According to Degree of Corrections a. Meniscus Lens = lens that has no correction. b. Rapid Rectilinear Lens – lens corrected of distortion c. Anastigmat Lens – correcting astigmatism d. Achromatic Lens – correcting chromatic aberration e. Apochromatic Lens – correcting both astigmatism and chromatic aberration INHERRRENT LENS DEFECTS 1. Spherical Aberration= Inability of the lens to focus light passing the side of the lens producing an image that is sharp in the center and blurred at the side. 2. Coma = (Also known as lateral aberration) = Inability of the lens to focus light that travels straight or lateral, thus making it blurred while the light reaching the lens oblique is the one the is transmitted sharp. 3. Curvature of Field = the relation of the images of the different point are incorrect with respect to one another. 4. Distortion = Is a defect in shape not in sharpness. It can either be Pincushion distortion (curving inward) or Barrel (curving outward). 5. Chromatic Aberration = Inability of the lens to focus light of varying wavelength. The lens refracts rays of short wavelength more strongly than those of longer wavelength and therefore bringing blue rays to a shorter focus than the red. 6. Astigmatism= is a form of lens defects in which the horizontal and vertical axis are not equally magnified. Inability of the lens to focus both horizontal and vertical lines. 7. Chromatic Difference of Magnification 8. Flares = condition of the lens producing multiple images. LENS CHARACTERISTICS 1. Focal Length – is the distance measured from the optical center of the lens is set to focus at infinite position. As according to focal lenses may be classified as: a. Wide Angle or Short Focus = with focal length not longer than the diagonal half of the negative. Useful in taking photograph at short distance with wider area coverage. b. Normal or Medium Focus = with focal length approximately equal but not longer than twice the diagonal half of the negative. c. Long or Telephoto Lens = with focal length longer than twice the diagonal half of the negative. Best used in long distance photographing but with narrow area coverage. d. ZOOM lens = lens with variable focal length or that which can be adjusted continuously by the movement of one or more elements in the lens system. 2. Relative Aperture – the light gathering power of the lens expressed in F-number a. Depth of Field – is the distance measured from the nearest to the farthest object in apparent sharp focus when the lens b. Hyperfocal distance = Is the nearest distance at which when a lens is focused with a given particular diaphragm opening will gives the maximum depth of field. 3. Focusing = is the setting of the proper distance in order to form a sharp image. The one that controls the degree of sharpness of the object. 6. CHEMICAL PROCESS The process of making the latent image visible and permanent. a. Development (Use of either D-76, Dektol or Universal Solution) = Is the process necessary for reducing the silver halides to form the image. Elon, Hydroquenone = used as main developing agents b. Stop bath = normally composed of water with little amount of dilute acetic acid that serves as a means to prevent contamination between the developer and the acid fixer. c. Fixation = Is the process by which all unexposed silver halides are dissolved or removed from the emulsion surface and making the image more permanent. Sodium Thiosulfate (hypo) is the main fixing agent that dissolves unexposed silver halides. Other chemicals used: Acetic Acid and Boric acid = serves as neutralizer Sodium Sulfate = serves as the preservative Potassium Bromide = restrainer or hardener Sodium bicarbonate and borax powder = serves as accelerator Dodging = is the process of eliminating unwanted portion of the negative during enlarging. Cropping = is the process of omitting an object during the process of enlarging and printing. Vignetting = is the gradual fading of the image towards the side through skillful adjustment on the dodging board. Dye toning = is the process designed in changing the color tone of the photograph. Burning-In = refers to additional exposure on a desired portion of the negative used for purposes of making a balance exposure.

Photography

The art and science of reproducing images using light and a camera.

Forensic

Relating to the administration of justice and used in conjunction with other sciences.

Police Photography

The application of photography principles in police work and the administration of justice.

Photograph

The mechanical and chemical result of photography, an image produced through the process.

Personal Identification

The first application of photography in police work, used for supplementary identification.

Communication

Photography as a universal method of communication.

Record Purposes

The use of photography in documenting and preserving evidence.

General View

Taking an overall view of the crime scene to show direction and location.

Medium View

Dividing the crime scene into sections to best view the nature of the crime.

Close-up View

Taking individual photographs of evidence to show details.

Extreme Close-up View

Using magnification to capture minute details in laboratory photography.

Preservation

Using photography to preserve the initial condition of the crime scene.

Discovering and Proving

Extending human vision through photography, including magnification and the use of artificial light.

Court Exhibits

Using photographs as evidence in court, proving relevancy and origin.

Crime Prevention

Using advanced photographic equipment, such as hidden cameras, to detect and prevent crimes.

Police Training

Using photography as instructional material in police training and other agencies.

Reproducing and Copying

Making multiple reproductions of evidence for examination without compromising the original.

Light

Electromagnetic energy that travels in waves, with a speed of 186,000 miles per second.

Camera

A light-tight box that blocks unwanted light from reaching the sensitized material.

Lens

The light-gathering mechanism of the camera that forms the image.

Sensitized Material

A highly sensitized chemical compound capable of transforming into an image through light and chemical processes.

Chemical Process

The necessary process for producing a latent and positive image from silver halides.

Theories of Light

The wave theory, corpuscular theory, and modified wave theory explaining the nature of light.

Types of Light

Visible and invisible light, including X-ray, ultraviolet, and infrared rays.

Photographic Rays

X-ray, ultraviolet, visible, and infrared rays used for different photographic purposes.

Light Source

Natural light (sunlight, moonlight, starlight) and artificial light (fluorescent, incandescent, photoflood).

Sensitized Material

Film and photographic paper composed of emulsion containing silver halides suspended in gelatin.

Types of Film

Black and white film and colored film (negative and reversal types) used in photography.

Spectral Sensitivity

The responsiveness of film emulsion to different wavelengths of light.

Infra-red Film

Sensitive to all colors and to infra-red light.

Film Speed (Emulsion Speed)

Refers to the degree of sensitivity of the film to light.

ASA (American Standards Association)

Expressed in arithmetic value system. The bigger the number, the more sensitive the film is.

DIN (Deutche Industre Normen)

Expressed in logarithmic value system. Used in the same principle as the ASA.

ISO (International Standard Organization)

Expressed as a combination of ASA and DIN rating.

Photographic Paper

Sensitized material that records the visible image in the final development and becomes the photograph.

Silver Chloride Paper

Used for contact printing, low sensitivity to light, gives blue-black tones when properly developed.

Silver Bromide Paper

Used for projection, printing, and enlarging process, gives a black tone when properly developed.

Silver Chlorobromide Paper

Used for both projection and contact printing, slow emulsion.

Variable Contrast Paper

Combines contrast range in one paper, produces varying contrast responses upon exposure to different colors of light.

Light Weight Paper

Designed for high flexibility and folding purposes.

Single Weight Paper

Used for small prints or fine details necessary in production.

Double Weight Paper

Used for large prints, stands up under rough treatment.

Glossy Paper

Designed for fine details and brilliant image formation.

Semi-matte Paper

Obscures fine details.

Rough Paper

Used for large prints or when breadth is necessary over detail.

White Paper

Better used in police photography.

Cream Paper

Preferred for pictorial effect, portraits, landscapes, or when a warmth effect is desired.

Buff Paper

Prepared for tone prints.

Velox No

Used for printing extremely contrast negative or extremely exposed film.

Velox No

Used for high contrast negative (overexposed film).

Velox No

Used for normal exposed film.

Velox No

Used for negative with weak contrast (underexposed).

Velox No

Used to provide sufficient contrast for thin or weak negatives.

Velox No

Used for flat negatives that are unprintable.

Camera

A light-tight box with a light-gathering device and a means of blocking unwanted light from reaching the sensitized material.

Light Tight Box

Designed to keep light out and hold other parts of the camera.

Lens

Collects or focuses reflected light from an object to form an image on the film.

Shutter

Controls the time during which light reaches the film.

Holder of Sensitized Material

Holds the sensitized material to prevent multiple or blurred images.

Viewfinder

Determines the field of view or extent of coverage of the lens.

Viewing System

Provides a means of showing the entire scene coverage that can be recorded.

Film Advancer

Transfers exposed film to the take-up spool for another exposure.

Shutter Speed

Regulates the time exposure of the film, expressed in a fraction of a second.

Lens Aperture

The ratio between the diameter of the lens opening and the focal length of the lens, expressed in F-number.

Focusing

Mechanism designed to control the degree of sharpness of the object to be photographed.

Range Finder

Focusing device that shows a double image that coincides when the object is in focus.

Ground Glass

Focusing device that shows a blurred image when the object is not in focus and becomes sharp and clear when adjusted.

Scale Bed

Focusing device that estimates the distance of the object and adjusts the camera control accordingly.

View Finder Type

Smallest and simplest type of camera.

Single Lens Reflex Camera

Best suited for police work due to interchangeable lenses.

Twin Lens Reflex Camera

Camera with dual lenses for focusing and forming the image.

View or Press Type

Biggest and expensive type of camera, used for movie making.

Lens

The image-forming device of the camera that has a greater effect on the quality of the image.

Positive or Convex Lens

Thicker at the center, capable of bending light together and forming the image inversely.

Negative or Concave Lens

Thinner at the center, forms a virtual image on the same side of the lens.

Meniscus Lens

Lens with no correction.

Rapid Rectilinear Lens

Lens corrected for distortion.

Anastigmat Lens

Lens correcting astigmatism.

Achromatic Lens

Lens correcting chromatic aberration.

Apochromatic Lens

Lens correcting both astigmat