With all else equal, which shutter speed is better able to stop motion?
1/400th of a second
An aperture of f/8 allows twice as much light as f/16 to enter the camera.
false
Which ISO value is the most sensitive to light?
ISO 3200
Which ISO setting should be used for "Examination Quality" photographs?
ISO 100
Match the following terms to their correct definitions.
Polarizer
filling the frame
diopter Adjustment
white balance
Terms:
a. camera setting that deals with temperature of ambient light
b. control knob that allows one to adjust the focus on the viewfinder
c. zooming in on the subject of interest to reduce background
d. a filter used to reduce glare
polarizer- d
filling the frame- c
diopter adjustment - b
white balance- a
A camera's light meter attempts to find an _________ gray value as a light-balanced exposure.
18%
What is the rule of thumb regarding "handheld" photography?
The shutter speed should not be any slower than one over the lens' focal length
To ensure crime scene photos are in proper focus, CSI investigators will try and use what f-stop settings?
f/11 or f/16
What is a stop of light?
one- half or twice the next full value of light
Which focal length is considered the "normal" lens focal length?
50nm
As the distance light travels is doubled, its intensity...?
is quartered
What factors affect how much light reaches the film plane?
-aperture setting on the camera
- shutter speed setting on the camera
-reflectivity of the scene
- amount of ambient light at the scene
The following are all cardinal rules of crime scene photography except?
- maximize depth of field
- fill the frame
- keep the film plane parallel
- when taking "critical comparison" or "examination quality" photographs, always utilize the highest ISO value available
When taking "critical comparison" or "examination quality" photographs, always utilize the highest ISO value available
The photographic log should contain the following information except:
- the case number
- make and model of camera
- photographer's name
name of the suspect in question
name of suspect in question
One key to an accurate image is to ensure that the scale is in the same focal plane as the subject.
true
A benefit of working in Manual mode is that this mode allows the photographer to easily adjust exposure values in conflict with what the camera's light meter suggests.
true
What photographs should be taken at a crime scene?
- location of the victim, perpetrator, objects of interest, and any witnesses when you arrive on scene
- point-of-view of witness, victims, perpetrator, etc
- implements or contraband
- injury or damage to people or items
For digital cameras, it is better to overexpose your images.
false
What is(are) the difference(s) between lossy compression and lossless compression?
- Image files compresses using lossless compression can be recreated exactly as they were captured when they are decompressed for viewing on a monitor or printing
- Lossy compression is a technique for reducing the file size of a digital image where the tradeoff is the loss of image quality for a smaller file size
JPEG images are an example of:
lossy compression
An image file that is simply the unprocessed sensor data from a camera is known as a?
RAW file
When utilizing a scale in the picture, the following guideline(s) should be followed:
- use an assortment of different length scales depending on your subject size
- place the scale at the same level or plane as you object
- utilize different color scales depending on your background subject color
- place the scale next to the evidence being photographed without compromising integrity of the evidence
all of the above
You accurately meter an exposure at ISO 200, f/5.6, for 1/500th of a second. You wish to bracket the exposure by adding one stop of light. What would be the new exposure values?
- ISO 400, f/5.6, for 1/500th of a sec
- ISO 200, f/5.6, for 1/250th of a sec
ISO 200, f/4.0, for 1/500th of a sec
any of the above
Which value allows three more stops of light into the camera than provided by an ISO 100 setting?
ISO 800
Zoom lenses
Allow the photographer to capture images at a variety of focal lengths
Which filter is recommended for all camera lenses?
UV
What are the basic operating modes of the” typical” modern digital camera?
Program, Aperture Priority, Shutter (time) Priority, and Manual
A shutter speed of 1/250th of a second allows twice as much light as 1/500th of a second to enter the camera, True or False?
true
Which value is one stop less light than provided by an aperture f/8?
f/11
Digital cameras have continued the convention of relating the sensitivity of their digital sensors to light by using the same ISO equivalents found in conventional film. The following are all true about ISO settings Except:
- the higher the ISO number, the more sensitive to light
- the higher the ISO number, the less light is needed for proper exposure
- an ISO setting of 100 should be used, if possible, when making "examination quality" photographs
- the higher the ISO number, the more "noise" may be seen in the photographs
all of the above are true
the smaller the f-stop number is, the more ______ the lens is.
the bigger the f-stop number, the more ____ the lens in
open, closed
All imaging sensors in a digital camera use a Color Filter Array (CFA) to capture the density of light that strikes each photo receptor, True or False?
true
Which is NOT one of the aspects of quality crime scene photographs?
Biased Material Relevant Accurate
biased
What is the brand of camera provided to you for laboratory?
Canon Rebel RX 5
Depth of Field is defined as:
the composition's area of sharpness
Which does NOT have an effect on an image’s depth of field?
- Shutter speed
-f/stop
-Point of focus within the image
-How far away the photographer is standing from the subject
shutter speed
When does Kodak recommend to take vertical photos?
when photographing a doorway
Which one of the following is NOT one of Kodak's Top Ten Tips for better photography?
Maintain shutter speed
Which of Kodak's tips helped you the most in lab. Explain why.
Lock the focus helped me the most when photographing in lab. When I photograph an object, I am always trying my best to be aware of the object of interest. If I focus too much on the background, it can lower the effectiveness of my photographs.
List at least three "camera care" guidelines to follow.
- Store in a dry, cool area
- always wear the camera strap to avoid dropping it
- Keep lens cap on when camera is not in use
Describe the relationship between shutter speed, aperture, and ISO values.
They are all reciprically related because whenever the ISO is increased, the brighter and grainer the image will be. The apeture relates to the opening of the camera, so when the opening is smaller, there is a higher f-stop. This means that the depth of field will be greater. In contrast, a wide apeture will have a smaller depth of field. Additionally, a lower shutter speed will take a longer time to take a photo and is ideal when the camera is on a tripod. If the shutter speed is higher, it will shutter an image faster and is ideal for capturing motion. Ultimately, ISO, shutter speed, and apeture can be adjusted depending on the situation to allow for more or less light to be detected in the camera.
With respect to photographs, what does the phrase "true and accurate representation" mean?
It means that your photographs should be as close to reality as possible. This will avoid any confusion or bias when your photographs are being examined.
Digital recordings of latent fingerprints should be recorded:
with 1000 ppi of capture
The following are all examples of photographic accessories to compose macrophotographs Except…
- Diopter filter set
- Extension tube
- Reverse rings
- "macro" lenses
all of the above
Why utilize an “external” flash as opposed to the camera’s “built-in” flash?
-It is more powerful
-It can be angled for bouncing the light off of a wall or ceiling
-It can be removed from the hot shoe and directed obliquely at your subject
- "Side” lighting gives you more “dimensionality” compared to “front” lighting
all of the above
“Examination Quality” photographs are photographs taken at the proper resolution, angle, lighting, and scale, to allow for additional forensic comparisons, True or False?
true
Why is there no set formula for proving relevance of an item of evidence for a case?
This is because any item in a crime scene can be used as evidence depending on the context of the scene. It is also better to not rule out any item of evidence as a photographer.
What type of images are considered category 1 photos?
- general crime scene photos
- arrest photographs, such as mug shots
- autopsy images
What type of images is considered category 2 photos?
- pattern evidence
- latent prints
- impression evidence
In order to record luminol reactions, one must remove all ambient light from the area being photographed.
false
List and explain the three series of images that should be taken to completely document a crime scene.
long range
short range
midrange
- long range shot: to establish location of scene
- mid range shot: to show the relation between different pieces of evidence
- close up: to have a closer look at a piece of evidence for evaluation
What effects the admissibility of photographic evidence into court?
- Must be relevant to the issues of the case
- must be true and accurate representation of a crime scene
- Probative value must outweigh prejudicial effects of photographs
all of the above
Select all options that are considered to be best practices in digital image enhancement.
A. You must have and follow a Standard Operating Procedure (SOP) that defines the complete digital imaging process
B. You must maintain an enhancement history of your digitally processed image
C. You must start with any image of the subject
D. You must preserve the original image
A, B, D
In macrophotography work, we are usually trying to fill the frame with a magnification ratio of…
1:1
considered pertinent or applicable in deciding the facts or issues in question
relevant
evidence that may cause a significant reaction/emotion from the jury and could create a bias
prejudicial effect
has some substantial importance
material evidence
the ability of an item of evidence to assist in the exploration of an issue
probative value
An image that is described to have very low dynamic range means:
The peaks are present in only a small fraction of the histogram
Select all effective alternative to direct flash lighting?
A. No lighting
B.Diffused lighting
C. Ambient lighting
D. Bounced lighting
B, C, D
A “True and Accurate Representation” refers to photo documentation of the scene as it originally appeared to the photographer, that is, with a “minimal” amount of distortion due to lighting, focal length, composition, etc., True or False?
TRUE
Typically, you should not use a flash in rainy or snowy conditions, True or False?
true
Why utilize a “tent” when photographing evidence up close?
The “tent” will give you even illumination without any shadowing
In macrophotography, the higher the magnification…
- less depth of field
- the more light is necessary
- the more difficult the project
all of the above
What does it mean when a piece of evidence is determined to be "transient"?
When a piece of evidence can be easily cleaned up or removed.
With telephoto lenses, their weakness is “perspective distortion” in the form of foreground-to-background compression. True or False?
true
When standard flash units are simply not powerful enough to adequately cover large outdoor crime scenes (and accessory lighting is not available), the following technique should be done?
paint with light
When photographing “shiny” or “polished” objects, or “small” crime scenes, the following technique should be done to avoid creating “hotspots”?
bounce flash
When photographing in daylight, the following technique should be done to “lighten” “shadowed” areas where evidence might be located?
fill-flash
The first systematic attempt at personal identification is known as:
Bertillonage
You should try to avoid using the highest f-stop lens setting (f/22) because at this smallest aperture opening, you are likely to get some diffraction, True or False?
false
What does SWGIT stand for?
scientific working group- imaging technology
Which image does NOT have to be recorded in the RAW format?
- tire track impressions
- bite marks
- visible fingerprint impressinos
- suspect line-ups
suspect line ups
What are some commonly accepted advanced enhancement techniques of category 2 images?
A. fourier analysis
b. noise reduction
c. all of the above
d. advanced image sharpening
c. all of the above
A polarizing filter can be utilized in photography to reduce glare from surfaces, such as glass, True or False?
true
(Picture with the shoe and chair) Which of the following makes this photograph shown, a poor example of good crime scene documentation?
a. no scale in picture
b. possible cross-contamination of trace evidence
c. not an "examination quality" photograph
d. the film plane angle
e. all of the above
E. all of the above
When photographing a luminol reaction, what would be a good starting point for exposure settings?
ISO 400 and f/8
Looking through your lens backwards creates a magnifying glass effect, true or false?
true
When photographing a black, soot-stained surface, what is the camera likely going to do with the exposure?
overexpose the photo
When using the Levels function in Photoshop, to adjust the shadows and highlights of an image, you should be careful not to clip to many pixels (any pixel values that fall between the new black slider point and 0 will be permanently lost, and any values that fall between the new white slider point and 255 will be also be lost). This statement is generally True or False?
true
Why is it important to save a copy of an original photograph, along with a copy of an edited photograph?
It is important because there it will allow for the person that is looking back at your photos to look at the things you edited. This can also allow for your photos to be considered credibly and reliable.
What methodology is used to capture indoor overall images?
Four-corners method
Category 2 images can be defined as:
Evidentiary images used for scientific analysis and comparison
Magnification ratio is defined as:
The relationship between the size of the in-focus subject’s projection on the imaging sensor and the subject’s size in reality
“Hotspots” can be defined as:
A bright spot within your image, causing overexposure
The minimum focusing distance for a typical 50mm lens is about
18 inches
What are the negative effects of using diopters to increase magnification?
Focus becomes soft when more than one filter is stacked on top of one another
When photographing blood on glass, what is a camera setting should you consider?
You should consider decreasing the f-stop in order to allow for the blood to be more in focus than the background.
What is the purpose of taking evidence photos without a scale being present?
For court purposes, shows the crime scene without any modifications
blood tend to ______light, which can prevent the stains from being seen in images
reflect
Category 1 images can be defined as:
Documentation images used to record a time, place, or event
“Built-In” flash units are:
- convenient
- least powerful
-inconveniently places
- may cause red-eye problems
all of the above
Category 1 images should be captured using JPG file formatting, true or false?
true
When can a flash that is attached directly to the camera’s hot shoe be problematic?
- photographing reflective surfaces
-macro photography
- portrait photography
All of the above
- images that are free for public use
- non-copyrighted images
- many free and public websites have collections of public images for individuals to use without copyright, permissions, and citation issues
public images
1. Complete an application form
2. pay a filing fee
3. submit a copy of the work you want to register
how to file a copyright
A group of rights over an artistic work that gives the copyright owner the exclusive right to display, sell, amke, distribute the work or create adaptations based upon the original work.
- includes records, books, poems, plays, paintings, photographs, and more
copyright
- involves the transformation or alteration of a photograph
- Depending on the motive behind manipulating a photograph, it can be seen as a skillful artwork or an unethical practice
doctored image
how can we tell if an image is altered?
- Check the JPEG image compression quality
- reverse image search
- Look for warping and digital distortion
- shadow discrepancies/inconsistent lighting
- unnatural colors
- Poor removal of objects
- Repeated or copied patterns
- no depth of field within the image
- free website and tools for digital image analysis
- has tools such as : error level analysis, meta data extraction, detection, JPEG quality and more
forensically (analysis tools for public use)
- free platform that gives access to valuable tools used in digital forensic analysis
- have similar tools and functions as listed above
FotoForensics (analysis tools for public use)
- established in 2008, Italian based company
- company and teams comprised of experienced forensic photo and video experts
- offers analysis services but also educational clinics and programs to help other agencies learn and develop their digital forensic analysis
Amped Software
- create or enhance contrast through fluorescence
- light/energy below 400 nm
UV photography
- forgery and document alterations
- fibers and other trace evidence
- semen,, blood, and other bodily fluids
- bruises or bite marks
-gunpowder residue
- fingerprint enhancements
UV light applications
What are the stages of bruises?
red ( 0-2 days), blue (2-3 days), green (5-7 days), yellow (7-10 days), brown (10-14 days)
- applying light of 700 nm or higher to evidence
- directly apply the light to the evidence or reflect the light, but filters will be needed to block all visible light from entering the camera and only view the _ light
IR photography
- enhancement of tattoos
- document examinations and forgery investigations
- gunshot residue
- bloodstain evidence
IR light applications
In what type of crime scene environment would you most
likely
utilize "Quadrant Mapping" for documentation?
Most likely used in large, complex, or outdoor scenes where
the
area is divided into smaller grids for systematic documentation.
Why is it important to photograph bruises over several days,
and
what do the "stages of bruising" typically indicate to an investigator?
-Importance: Bruises change over time; photographing them over
several days
documents the healing process.
- Indication:
The "stages of bruising" (color changes) help investigators
estimate
the approximate age of the injury.
Beyond the visual appearance, what are two ways a
forensic
investigator can tell if a digital image has been
"doctored" or altered?
-Detection Methods: Examining the Metadata for inconsistencies,
checking the
-History Log for unauthorized edits, or using
specialized analysis tools.
List three specific pieces of information that should be recorded
in
a professional forensic photo log.
Any three of: Case number, date/time, location, photographer identity, camera/lens used, and a description of the subject of each photo.
What is "Metadata," and why is the "History Log"
of an enhanced
image vital for its admissibility in court?
-"Data about data" embedded in the file, including camera
settings, date, and time.
- History Log: It provides a record of
all enhancements, ensuring the image remains a fair and accurate
representation and that the process can be replicated in court.
Provide one forensic application for Ultraviolet (UV) light and one application for Infrared (IR) light.
- UV: Detecting bodily fluids (semen, saliva) or bite marks.
-IR
Application: Visualizing gunshot residue (GSR) on dark fabrics or
seeing through blood to find underlying patterns.
Why is it critical to use a scale (ruler) when
taking
"Examination Quality" close-up photos, and what
is one guideline for its placement?
- It provides a size reference for 1:1 comparison or analysis.
-
must be placed on the same plane as the evidence to
avoid
perspective distortion.
-political propaganda
- changing appearances of individuals
- making objects look more appealing to the viewer
- AI
areas that utilize doctored images the most