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FRSC 513 - Forensic Photography
Final Exam Study Guide for GMU FRSC 513
98
Criminal Justice
Graduate
12/07/2020

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Cards

Term
When do you want to use a flash?
Definition
When there is not enough light: early morning, late afternoon, night, indoors; when the right quality of light is needed to eliminate tints
Term
What is the guide number?
Definition
It is the designation for the flash unit's relative output power.
Term
What is the standard flash's GN number?
Definition
120
Term
When using a flash what should your shutter speed be?
Definition
Whatever the sync speed of the camera is
Term
What is the equation for the f/stop?
Definition
GN/Distance = f/stop
Term
What is the GN for the built in flash?
Definition
36
Term
Why don't we use the built in flash?
Definition
The GN number is really small, which requires a wide aperture and has a super limited DOF, creates hotspots, and red eye
Term
What is the sync speed?
Definition
The speed of which the shutter is open while the flash fires
Term
What happens if you use a shutter speed faster than the sync speed?
Definition
The shutter will be in the picture
Term
What happens if you use a shutter speed slower than the sync speed?
Definition
Usually nothing, but if very slow it may cause blurred images and or ghost images
Term
What are the flash stop increments and what are these 1 stop increments called?
Definition
1, 1/2, 1/4, 1/8, 1/16, Vari-Powers
Term
How do you decrease the amount of light when using a flash?
Definition
use vari-stops, move away from subject
Term
How do you increase the amount of light with a flash?
Definition
Move closer, open the aperture
Term
What is a normal room for flash?
Definition
ž“Normal” 10’ by 12’, light color walls, with 8’ or 9’ ceilings
Term
What are non-normal rooms?
Definition
smaller than normal, larger than normal, outside, dark colored walls, and reflective surfaces
Term
What is a hot shoe?
Definition
It is the mount on the camera for the flash
Term
Rule of Thumb: When you are 5’ or closer to your subject, remove the flash from the hot-shoe, so it can accurately be aimed at your target. Why?
Definition
To removed hot spots, red eye, and the flash is above the subject that close
Term
What allows the flash to be off camera and still work?
Definition
PC / Remote Cord
Term
When using a PC / Remote cord, how far should it be from the subject and why?
Definition
at least 2 feet to avoid over exposure
Term
What is red eye in photography?
Definition
It is the reflection of the blood vessels in the back of the eye.
Term
How do you fix red eye?
Definition
Keep the flash off the direct axis
Term
How must the flash be oriented?
Definition
In the same manner as the subject (vertical vs horizontal). Think FTF
Term
True or False: Flash and Camera must be oriented correctly in the horizontal of vertical manner of the subject.
Definition
True
Term
True or False: Flash heads must be set to the focal length of the lens (wide/norm/telephoto)
Definition
True
Term
What does the flash diffuser do?
Definition
Diminishes light and Diminishes Glare
Term
What are the ways to achieve a -1 stop with a flash without changing any camera settings?
Definition
Place one finger in the cent of the flash or put one handkerchief over the lens
Term
Explain the inverse squared law.
Definition
As distance doubles, light is quartered; 2D=I/4
Term
What is the result of the inverse squared law?
Definition
f/stops
Term
How does automatic flash work?
Definition

žRelies on reflected light (18%) being sensed by the flash sensor eye and the sensor will cut off light duration to prevent overexposure

Term
What are the advantages of automatic flash?
Definition
Save battery, less recovery time in between flashes, uses flash ranges
Term
In regards to flash, what does TTL stand for and mean?
Definition
Through The Lens (TTL) means the flash is being controlled by the camera body's sensor
Term
When is fill flash used?
Definition
In a scene with strong ambient light and shadows
Term
When performing the fill flash technique, where do you meter and then aim the flash?
Definition
Meter in the bright area, but aim the flash where it is most needed. Make sure to set the flash -1 stop
Term
Where is the flash aimed with bounce flash?
Definition
Midway or closer, but not past the midway point of the light will hit behind the object
Term
When is oblique lighting used and why?
Definition
It is used when photographing 3D impression evidence. This creates shadows which show depth to the impression in a photograph
Term
Why use a remote or timer with a camera?
Definition
Because the manual depressing of the shutter release can cause camera shake
Term
What photographs do you take prior to close up photographs?
Definition
Midrange photographs
Term
What is the sequence for photographing close up photographs?
Definition
Establish with location midrange, take one photo as is with no scale, multiple directions and angles with scale,
Term
True or False: A scale must be on the same plane as the item being photographed?
Definition
True
Term
How much of a tire tread must you photograph to get the whole circumference?
Definition
7.5 feet
Term
How do you break up the segments tire tread to photograph them for comparison?
Definition

žSplit into 1 ½’ segments, overlapping 1”

—A = 0” to 19”

—B = 18” to 37”

—C = 36” to 55”

—D = 54” to 73”

—E = 72” to 91”

Term
Why use snow wax in photographing impressions in snow?
Definition
Creates contrast, allows the cast to set (dental stone gives off heat and will melt the stone)
Term
What must be included in the photo identifier card?
Definition
Case Number, Date, Location, Photographer Name, and roll/memory card number
Term
What information should be included on a labeled scale?
Definition
Case Number, Item Number, Date, Photographer's initials
Term
True or False: Anytime one of the variables on the photo identifier card changes, a new photo identifier card needs to be photographed.
Definition
Ture
Term
True or False: When scales are used they should be positioned on the same plane as the evidence.
Definition
True
Term
Explain the "body panorama" sequence of photographs.
Definition
Make sure to establish the body with a mid range photograph and then take photos of all four sides and then a frontal picture of the face. Document wounds and when that is done turn over the body and repeat.
Term
What are two reasons why every photograph should be documented on a photo log?
Definition
The photo memo sheet can be used to refresh memory at court and it allows the user to document errors in order to prevent future errors.
Term
Why would you cover up "sensitive" areas of a living body when documenting wounds?
Definition
It preserves the modesty of the person being photographed as well as those viewing the photos.
Term
What are the 3 reasons a labelled scale is included in close-up photographs?
Definition
The scale shows the size of the object/evidence being photographed. The scale allows the examiner to blow up the photo for comparison. The labeling information helps document the image.
Term
What is the purpose of taking midrange photographs?
Definition
They establish a special relationship between two objects, usually an item of evidence and a fixed object to show where somethin is in the scene.
Term
Fully explain what areas do you photograph during exterior overall photographs?
Definition
Walk the viewer from the outer perimeter in. Take pictures of the cross street, emphasizing the street of the crime, take photos from the sign to the scene. At the scene take outside 360 photos of the building and take a photo of the address sign. Photograph the immediate area and entrances and exits.
Term
Why is a photo identifier card used?
Definition
It allows every photograph to be associated back to the photographer and specific crime scene
Term
When is the best time to log photos on a photo log?
Definition
Immediately
Term
When is a labeled scale used?
Definition
Close-up photographs with scale
Term
Overall and midrange photographs are taken from what perspective?
Definition
Natural perspective
Term
True or False: When taking diagonal photographs of the outside 360 you have to take 360 photographs at each corner.
Definition
True
Term
Explain interior overall photographs.
Definition
Start from the entrance, use a normal lens, photograph corner to corner, floor to ceiling, walk the viewer through the scene using proper orientation.
Term
What are some issues with taking FPP interior overalls?
Definition
Hotspots, Non-normal scenes (lots of white walls), reflections, shadows
Term
What f-stop is optimal for close up photographs and why?
Definition
F/11 because of diffraction
Term
Explain the sequence to photograph evidence for close ups.
Definition
Establish the evidence with a midrange photograph. Take an in situ photo with FTF and FPP, ISO 100. Then take another photograph of the item with scale
Term
What is an easy way to show that the close-up is an altered close-up?
Definition
Chane the background
Term
When taking a midrange of an injury where do you relate it to?
Definition
To a major joint. Make sure to have proper orientation and form an isosceles triangle
Term
At the autopsy why is a photo of the sealed bag taken?
Definition
To document chain of custody
Term
Define Electromagnetic Spectrum
Definition
The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation
Term
What wavelengths are the visible spectrum?
Definition
400-700nm
Term
What wavelengths are Infrared?
Definition
700-1100nm for photography
Term
What wavelengths are ultraviolet?
Definition
100-400nm
Term
Define Fluorescence
Definition
It is the conversion of light from one state to another, usually light of a longer wavelength and lower intensity
Term
Define nanometer
Definition
1billionth of a meter
Term
How is a wavelength determined?
Definition
It is the distance between beak to peak
Term
Provide an example of a short wavelength
Definition
X-Rays, gamma rays
Term
Provide an example of long wavelengths.
Definition
Microwave and radio waves
Term
Which is a longer wavelength, UV or IR?
Definition
IR
Term
What are the four ways light can react to different surfaces?
Definition
Reflection, Absorption, Transmission, and Fluorescence. Fluorescence is the conversion of light from one state to another.
Term
What color will the total reflection of all light be?
Definition
White
Term
What color will the total absorption of all light be?
Definition
Black
Term
Explain how colors are seen in regards to reflection.
Definition
White is the total reflection, black is the total absorption, and then the colors you see are the colors reflected back.
Term
What is transmitted light?
Definition
Most of the light goes through the surface, but some is absorbed. Think of tinting on a car or a handkerchief on a flash
Term
Why do we need to wear a filter to see fluorescence?
Definition
The emitted light is weaker than the original source. Therefore you need to eliminate the overwhelming original source to see the fluorescence
Term
What color filter is used with a VU light?
Definition
UV filter or a Yellow Filter
Term
What color filter is used with a blue light?
Definition
Orange filter
Term
What color filter is used with a green light?
Definition
Red filter
Term
What nanometers is blue?
Definition
430-480nm
Term
What nanometers are shortwave UV?
Definition
280-315nm
Term
What is a piece of equipment that uses shortwave UV?
Definition
RUVIS (Reflected UV Imaging System)
Term
What wavelength is longwave UV?
Definition
315-400nm (black light)
Term
True or False: Shortwave UV (280-315nm / UVB) should not be used on evidence requiring DNA examinations.
Definition
True
Term
What type of UV light is considered germicidal?
Definition
UVC
Term
What type of UV light is considered tanning UV light?
Definition
UVA (315-400nm)
Term
What type of UV light is sun burning light?
Definition
UVB (280-315nm)
Term
What wavelength is UVC?
Definition
Less than 280
Term
What wavelength is UVB?
Definition
280-315nm
Term
What wavelength is UVA?
Definition
315-400nm
Term
What are the four applications of IR photography?
Definition
Visualizing Ink differentiations, Visualizing GSR, Visualizing the writing on burned documents, Visualizing blood stains
Term
True or False: Bones fluoresce
Definition
True
Term
What or the effects of IR light on different substrates?
Definition
Absorption: Darkens, Reflection: Lightens, Transmission: Disappears, Fluoresces: Longer wavelength with a weaker intensity
Term
Explain the Stokes Shift.
Definition
This is fluorescence. Some surfaces will absorb light that strikes them and convert that light to a longer wavelength with less intensity.
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