FIVS 210 Forensic Photography Exam 2

Anthropometry

the scientific study of the measurements and proportions of the body created by Alphonse Bertillon

began in France in 1883 and was in use until 1903

purposes of crime scene photography

record details of scene and surrounding areas

document initial appearance and location of physical evidence with respect to the crime scene

provide investigators, witnesses, and others to a permanent visual record

refresh memory of crime scene

review details

provide evidence

document an injury

quality crime scene qualifications

correct exposure

maximum depth of field

in focus

how to document a crime scene

long range, medium range, and close ups

long range photographs

used to establish an overall view of the crime scene location and potential evidence

overlap photographs to make connection between images

capture scene as initially found

medium range photos

establish location of evidence with respect to other items at crime scene

transition from distant to close range

evidence is obvious

close up images

ID evidence and establish location

fill the frame with evidence

90* angle - use a tripod

cardinal rules of crime scene photography

1. fill the frame

2. maximize depth of field

3. keep the film plane parallel

the three rules of investigative photography

1. if its worth looking at, its worth photographing

2. photograph everything before its moved or altered

3. document evidence with long, mid, and close up shots

photo log

records general info about the case, jogs memories, explains lighting, and specific settings

case identifier tag

the first photo in a set at a new case showing case number, photographer name, investigator name

inverse square laws

how fast light falls off and how far it spreads as the distance from the light source increases

Light Close for sharper shadows, bigger catchlights and darker backgrounds. Light Far for softer shadows, smaller catchlights and brighter backgrounds.

built in flash

convenient but weak

can cause red-eye

flash synchronization

built-in flash is timed to the exposure by the camera

the speed of the exposure must be slow enough to allow for the benefit of the flash

fill flash

lightens the shadows and reduces image contrast

reduces “hotspots”

bounce flash

bouncing the light off an object other than the subject to light up an area

diffused flash

softens and spreads out harsh, concentrated flash

painting with light

slow shutter speed used to lighten an entire area

takes a long time and uses an assistant

tripod components

SWIGIT

Scientific Working Group on Imaging Terchnology

provides guidelines and recommendations for use of imaging technologies

Category One Image

used to record a time, place or event

includes:

1. general crime scene images, including evidence

2. surveillance images

3. autopsy images

4. documentation of evidence in lab

5. arrest photos/mug shots

category two images

used for specific analysis and comparison

includes:

1. latent prints

2. bloodstain patterns

3. questioned documents

4. tool mark images

5. gunshot residue

6. impression evidence

bits of data

each 1 bit DOUBLES the number of combinations

meta data

additional information is embedded within the image file that provides more details

info includes:

1. caption info

2. photographer information

3. IPTC

4. camera data

5. image data

6. video/audio data

7. DICOM, XMP, EXIF

8. history

to view metadata

1. file info

2. history/photoshop tab

to enhance category 1 images

a detailed history is not required

1. adjust brightness/contrast

2. adjust color balance

3. adjust hue/saturation

4. adjust white balance

5. image sharpening

6. cropping

7. rotating

enhancement of category 2 images

the image MUST be RAW OR TIF and a detailed history must be maintained

includes:

1. tonal range corrections

2. color channel selection and subtraction

3. fourier analysis

4. noise reduction

5. image sharpening

how to start a history log

1. edit tab

2. preferences

3. history log

4. turn it on by saving log items to metadata and editing log items to detailed

dynamic range

values that span the entire histogram

the output if very intense at one setting

diopter

glass filters that can be added onto the end of a camera lens and stacked to zoom in further

+1, +2 or +4

when stacked, can soften the image and make focusing difficult

extension tubes

expensive, but can get close to the object without distortion

sharper images

shutter speed and exposure are effected

reversing rings

allows you to mount the lens backwards, making it a magnifying glass

macro lens

allows you to focus extremely close to a subject

true sensors will be 1:1

magnification ratio

the relationship between the size of the in-focus subjects projection on the imaging sensor and the subject’s size in reality

minimum focus distance: 18”

what is the purpose of evidence w/ and w/out a scale

a scale is utilized to capture important dimension info and a photo w/out can be used to show no modifications were made

with respect to photographs, what does the phrase “true and accurate representation” mean

refers to a photo documentation of the scene as it originally appeared

you are asked to determine the size of an item from a photo. explain the process

by utilizing the scale in the photo, a relative dimension can be obtained on any item in the image. the easiest way is to enlarge the item and print the scale to its natural size

what are the three series of photographs which should be taken to completely document a crime scene

overall, midrange, and closeup

what are 2 considerations when utilizing a scale?

1. scale at the same height as the subject

2. scale should be a similar shade as the subject/background

3. camera film plane should be parallel to the subject

4. scale should be an appropriate length

5. take a photo before the scale is placed

why utilize a flash fill

to lighten up a dark/shadowy area

why utilize a bounce flash

to avoid “hot spots” in the imane

why use an external flash?

it is more powerful and can be angled for bouncing light

why should you use flash from 3 different angles?

when directing light at oblique angles, you get better images, but there may be shadowing produced

what does examination quality photograph mean?

photos taken at proper resolution, angle, lighting, and scale

the rules of evidence provide 2 legal principles for digital imaging process. they may be used if

1. nothing material or essential has been added

2. nothing material or essential has been removed

when using the levels function, what should you be careful of

clipping