EXAM 2 Flashcards
Alphonse Bertillon
Discovered anthropometry; made the first systematic attempt at personal identification; method was based on 2 premises: the dimensions of the human-bone system remain unchanged from the age 20 and no two individuals have the same measurements at the 11 different locations chosen.
anthropometry
Began in France 1883; study of the measurements of the human body and its proportions; helped convict persons
Purposes of crime scene photography
- Record details of the scene and its surrounding conditions as is/ original condition
- Document initial appearance and location of physical evidence with respect to the crime scene
- provide investigators, witnesses and others with permanent visual records.
- Refresh memory of crime scene
- review particular details
- provide evidence for forensic comparison purposes
- document if an injury as occurred
- convey information in a court room
Admissibility of evidence is based on what 3 qualifications
- must be relevant to the issue of the case
- must be a true and accurate representation of the crime scene
- probative value (usefulness / relevancy) must outweigh prejudicial effect of photographs; does the potential benefit of proving the facts in the photograph outweigh any potential negative impact it could have on the fairness of the trial
Capturing quality crime scene photos include:
Photos must be:
1. correctly exposed
2. maximum depth of field
3. be in focus and distortion free
Documenting the crime scene
need photographs in long (overall), medium (mid-range), and close-ups
Long (overall) photographs
purpose is to establish to an overall view of the crime scene location an potential evidence; photos can be overlapped to make connections; capture the scene as originally found
Outdoor long photographs
- photograph landmarks
- aerial photos of scene and surrounding area
- photos at all angles
indoor long photographs
- photograph all four corer of the room to show the layout
- wide angle lens may be used in confined spaces to get complete coverage
Medium photographs
- establishes location of potential evidence with respect to other items at the scene
- transitions viewer from distance standpoint to a move involved POV
- evidence becomes more readily identifiable
Close up photographs
Used to clearly identify evidence and establish exact location; fill frame with evidence
- they should be photographed w/ and w/o scale
- photographs at 90%
Markers and placards
- aid to viewer recognition, location and orientation of evidence
- always take one photograph with and without the marking and measurement device
Scales
- establish the size of the evidence
- assist in forensic comparisons
Cardinal Rules of Crime Scene photography
- fill the frame
- maximize the DOF
- keep the film plane parallel
Rules of investigative photography
- if its worth looking at its worth photographing
- photograph everything before you move or alter it
- document w/ 3 shots: long, medium and close-up
What should be photographed?
- location of witness, perp, objects of interesst and any witnesses when you arrive on scene
- POV of witnesses, victims perpertrators, etc.
- injury or damage to people or items
- immplements or contraband
- debris, tire tracks, tool marks, fingerprints, palm prints, and footprints
- likely exit or entrance routes
- overall shots of the scene
handling the camera (tripod)
- focus 1/3 of the way to get max DOF
- use tripod if feasible or anything to support the camera
Photograph log purposes.
two purposes:
- recording general information about the case (help jog memory and explain lighting conditions)
- recording specific information about each photograph you take
Case Identifier Tag
First frame that is photographed at the crime scene is usually the Case ID tag. It tells information such as the case #, photographer’s name, investigators name, etc.
- easy way to identify a roll of film once processed
- decision on whether or not to photograph a Case ID tag is up to the photographer
What is the purpose of taking evidence photos with and without a scale?
A scale is utilized to capture important dimension information and a photograph without the scale is for court purposes to document the scene without any “modifications”
With respect to photographs, what does the phrase “true and accurate representation” mean? Explain as if you are speaking to a jury.
photos being presented must truly represent the crime scene as accurately as possible
You are asked to determine the size of an item of evidence from a photo. Explain the process of doing this to a jury.
By utilizing the scale in the photo, a relative dimension can be obtained on any item in the image. The easiest way to do this is to enlarge the image and print the scale to its “natural size.”
Inverse square law and how it relates to intensity
I = 1/d^2; farther from the flash, the less light
What are two considerations when utilizing a scale in your photographs?
- The scale should be at the same height as your subject.
- The scale should be a similar “shade” as your subject (black for dark backgrounds, ans white for light backgrounds, grey for neutral backgrounds).
- Your camera film plane should be parallel to your subject (or your lens axis should be perpendicular to your subject)
- The scale you use should be an appropriate length for your subject (don’t use a six-inch ruler for a tire track print).
- Take a picture of the item (at a crime scene) before you place a scale in the picture (shows the scene as you found it).
built in flash
- most convenient, but least powerful
- inconveniently placed can cause red eye or macro-photography coverage problems
- may be used to trigger other electronic flash (EFUs)
- may be used for fill outdoors
- built in flash must be diffused to minimize inconsistency of exposure for macro-photography
Flash synchronization
- built in flash is timed to the exposure by camera circuits
- accessory flash must be connected to the exposure
- no upper speed limit for flash synch.
- the speed of the exposure must be slow enough to allow for the benefit of the flash
Fill Flash
- always adjust the flash exposure, not the camera exposure, when using EFU
- fill flash should not change the overall exposure
- it should only lighten the shadows and reduce image contrast