FORENSIC MIDTERM Flashcards
A positive lens that is thicker on the middle than the edge. It also creates a real image.
CONVEX LENS
It is the most important and essential part of the camera.
LENS
A negative lens that is thinner on the middle than the edge and creates virtual image.
CONCAVE LENS
A complex aberration that affects only light rays from a point that pass through the lens at an angle.
COMA
A color distortion that creates an outline of unwanted color along the edges of objects in a photograph
CHROMATIC ABERRATION
Occurs when the lens fails to focus image lines running in different directions in the same plane.
ASTIGMATISM
The image of a flat subject does not
appear flat because of the sharpness of the center and the edge is out of focus.
CURVATURE OF FIELD
When the outer parts of a lens do
not bring light rays into the same
focus as the central part.
SPHERICAL ABERRATION
Three (3) types of distortion.
BARREL, PINCUSHION, AND MUSTACHE
An optical aberration induced by the composition of the lens.
DISTORTION
Created by the curved shape of the lens.
BARREL DISTORTION
Is a lens effect that causes images to
become pinched in the center and the most often associate with telephoto lenses.
PINCUSHION DISTORTION
The straight lines of an image bend outward from the centre, and then inward from the corners of the frame.
MUSTACHE DISTORTION
Six (6) types of lens aberration.
ASTIGMATISM, CHROMATIC ABERRATION, SPHERICAL ABERRATION, COMA, CURVATURE OF FIELD, AND DISTORTION
What are the types of correctional lens?
ACHROMATIC LENS, RAPID-RECTILINEAR LENS, ANASTIGMAT LENS, AND APOCHROMATIC LENS
Corrected for: distortion
RAPID-RECTILINEAR LENS
Corrected for: astigmatism but with
higher degree of correction to
color.
APOCHROMATIC LENS
Corrected for: chromatic aberration
ACHROMATIC LENS
Corrected for: astigmatism
as well as the other lens
defect
ANASTIGMAT LENS
Tells us the angle
of view—how much of the scene
will be captured—and
the magnification—how large
individual elements will be.
FOCAL LENGTH
It is how much of a scene is in sharp focus.
DEPTH OF FIELD
Is related to focal length but
is not dependent on it.
FOCAL DISTANCE
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.
MICRO PHOTOGRAPHY
Close-up photography, is used to capture small objects, such as trace evidence or tool marks in which their size is bigger than their actual size.
MACRO PHOTOGRAPHY
Used when photographing narrow and crowded spaces.
WIDE ANGLE LENS
Fixed lenses used in photographing long or far
distances.
TELEPHOTO LENS
Lenses that enlarges object and magnify to 9x.
MACRO LENS
Lens which commonly used in regular photography.
NORMAL LENS
It can photograph from the shortest to the longest distance.
ZOOM LENS
Transforms the latent image into a visible image, makes this permanent and renders it in sensitive to light.
PHOTOGRAPHIC PROCESSING
A photographic bag
specifically designed to be light-proof while in
use.
CHANGING BAG
It is a room that can be made completely dark to allow the processing of light sensitive
photographic material, including photographic film and photographic paper.
DARK ROOM
A light-tight
container used for developing film.
DEVELOPING TANK
The film clips to the center of
the reel and is gently rolled onto
the reel in complete darkness.
STAINLESS STEEL REEL
The film is loaded from the outside
and then wound onto the reel by
rotating the reel with a back-and-
forth motion.
PLASTIC REEL
One or more chemicals that convert the latent
image to a visible image.
DEVELOPER
The most important compound in a developer and an organic compound which actually makes the latent image visible.
DEVELOPING AGENT
A chemical used for processing black-
and-white photographic films, plates, and paper. It is used to neutralize the alkaline developer.
STOP BATH
A mix of chemicals used in the final step in the photographic
processing of film or paper.
FIXER
An apparatus used for making contact
prints, having a frame for holding
printing paper and negative together
and a light source for making an
exposure.
CONTACT PRINTER
It is a photographic image produced by laying the negative, typically a negative, directly against photographic paper and exposing the paper to light.
CONTACT PRINTING
A card of other opaque object is held between the enlarger lens and the photographic paper so as to block light from only a portion of the image intended to be lightened.
DODGING
It is the elimination of some part of the negative which are not to include in positive.
CROPPING
This is where a portion of a print is too bright after the main exposure.
BURNING
The higher the head the bigger the size of the image and vice versa.
ENLARGING
Final stage in making photograph.
PRINT MAKING
Electromagnetic spectrum from about 400 nanometers to 1 nanometer. Provides more details to an injured area as well as the revealing bruises and scars and to detect alterations of documents.
ULTRAVIOLET PHOTOGRAPHY
Uses in Law enforcement:
for photographic enhancement of rashes and other skin disorders; and
for detecting alterations in documents.
REFLECTIVE UV PHOTOGRAPHY (RUP)
Commonly used in forensics to detect and document biological substances (such as blood, semen, and other bodily fluids) at crime scenes.
UV FLUORESCENCE PHOTOGRAPHY (UFP)
Yes or No. Does infrared visible to human eye?
NO
What are the three (3) important things on developing photos.
DEVELOPER, STOP BATH , AND FIXER
He discovered the infrared radiation on 1800
William Herschel
Closer to the microwave section on the electromagnetic spectrum, can be felt as intense heat, such as the heat from sunlight or fire, according to NASA.
LONGER “FAR-INFRARED” WAVES
Closer to visible light on the electromagnetic spectrum, don’t emit any detectable heat and are what’s discharged from a TV remote control to change the channels.
SHORTER “NEAR-INFRARED” WAVES
Used by crime scene investigators as a non destructive test for examining gunshot residue (GSR) on dark and multi-colored fabrics found at the crime scene.
INFRARED PHOTOGRAPHY
A liquid that is used to reveal the bloodstains of a crime scene. An organic compound that exhibits chemiluminescence, or a glowing quality, when mixed with the iron found in blood.
LUMINOL
An even more detailed use of infrared technology in forensics. It allows forensic analysts to figure out exactly what a piece of trace evidence is made up of.
INFRARED SPECTROSCOPY
Is used as night vision devices, but at a higher magnification.These systems scan for visible light in night time settings and absorb it. This light is then magnified and depicted in images with a greenish tint.
Requires nearby visible light.
NIGHT VISION
A basic technology that works in the same way as a regular camera but amplifies any light available.
IMAGE INTENSIFIER
Is simply the process of converting infrared (IR) radiation (heat) into visible images that depict the spatial distribution of temperature differences in a scene. Is another useful technique used in law enforcement. people can be detected in complete darkness.
THERMAL IMAGING
