the amount of light that reaches your camera’s sensor, creating visual data over a period of time

Exposure

change that either halves or doubles the overall lighting from the original exposure

exposure stops

the distance between the nearest and furthest objects that are in acceptability sharp focus in an image captured with a camera

Depth of Field:

a camera setting that measure how sensitive the camera’s imaging sensor is to light

ISO

describes how the intensity of light changes as you move away from the source of light

• The farther you move away from the source, the less light will be able to reach you
• As distance from the light source to the subject doubles, the intensity of the light decreases by ¼ or two F-stops

Inverse square law:

1. Shutter speeds
2. Apertures
3. Film speeds/ digital ISO equivalents
4. The ambient lighting of the scene, or any supplemental lighting that can be used

Exposure Variables:

Reciprocity Between F-Stops, Shutter Speeds, and ISO “Normal” Lens:

• An ISO value like 100 is less sensitive to light resulting in higher resolution
• An ISO like 3200 is more sensitive to light and works better in the dark but can make photos grainy.

Exposure triangle

• Reference tool used to reduce the black noise in digital cameras, helping to set accurate exposure and white balance.
• It is a flat card that reflects 18% of the light that falls onto it, which represents this middle grey tone

18% grey card:

this is how long the shutter of your camera stays open

shutter speed

1. Body movement: use tripod to eliminate movement
2. Subject motion:
1. Slow shutter speed (½) lets in more light but also can cause motion blur
2. Fast shutter (1/1000) lets less light but also can cause motion blur is subject or camera moves
3. Should maintain at least 1/60 shutter speed to mitigate blur caused by handheld camera images
3. Camera movement

3 types of movement mitigated by shutter speed:

1. Wrap your hand around the camera grip firmly
2. Hold the lens bottom with you left hand
3. Rest you hands right index finger lightly on the shutter button
4. Press your arms and elbow lightly against your body
5. Maintain stable stance
6. Press camera against your face and look at viewfinder

stopping motion

- utilize camera strap

-protect camera from harsh elements

- use storage/carrying case to protect camera and equipment

- store camera in well ventilated, cool, dry area

camer care

-Protection of the lens

- reduction of haze

-warming

UV filter

-reduction of glare and reflection

- enhancement of color

Polarizing filter

- normal lenses focal length for the sensor format yields the most accurate reproduction of reality

- use wide angle and telephoto focal lengths only when absolutely necessary

Perpective

uses a mirror and prism system to allow the photographer to see through the lens

single lens reflex (SLR)

a digital version of the SLR, using a digital sensor to capture the image

digital single lens reflex

does not have a mirror and uses an electronic viewfinder to display image

digital single-lens mirrorless (DSLM) and mirrorless interchangeable lens camera (MILC)

camera nomenclature

- A tool the brain uses to experience the world around it

vision

- the process of becoming aware of the representation of an object or scene

- people accept photographs as reasonably accurate representations of objects and scenes, because we expect them to

perception

- Deviations from normal focal length may produce images with distorted perspective

- Linear perspective is a visual clue that creates the illusion of space and distance on a flat surface

- parallel lines that appear to converge

vanishing point

Kodak’s 10 Tips for taking better photo

- get down on the subjects

-use a plain background

-using the flash outdoors

-move in close

- take some vertical photos

- lock the focus

- move it from the middle

- know the flashs range

- watch light

- be a picture director

a technique to reduce the intensity of shadows and allows for details of the subject to be visible and well-balanced

fill flash

-when the object is fully in a photograph

filling the frame

-the data they record is the light intensity for each individual pixels on the imaging chips

- stored as a bunch of ones and zeros strung together in a binary code

- must convert raw files to JPEG or TiFF

RAW images

-removes some originally recorded information from the images

- are processed inside the camera itself

Lossy (JPEG)

-raw files are processed by the computer once you import the file

- can be used by examiners to make comparisons between known and unknown pieces of evidence

Lossless

-Fingerprints, footwear, tire marks, or any other impression evidence

- Bloodstain documentation

- bullet strikes and impacts

- tool marks

- reconstruction photographs

-bite marks

Examples of comparison/analysis photographs

- some types of evidence have a standard to follow when photographing

- This is to maximize the image quality

- fingerprints need to be photographed with a 1000 ppi ratio

- footwear and tire mark impressions need to be photographed with a 500 ppi ratio

pixels-per-inch (ppi) ratio

- need to know the size of your imaging chip

- divide the horizontal and vertical pixels by 1000

- the results is the max image capture size in inches

- you msut then convert the inches to millimeters

How to determine ppi?

mosaic patter of color, color filter array (CFA)

positioned on top of the sensor to filter out the red, green, and blue components of light falling onto it

examination quality photos

correlates with having an ISO of 100

number is the focal length of the lens divded by the diameter of the opening

f-stop

name from top to bottom

1. to digitally see the image

2. change the apeture settings (f-stop and shutter)

3. how much light hits sensor

4. menu

5. to look at images

a process used to estimate the color of missing pixels in an image and can affect image quality by introducing artifacts or reducing sharpness

interpolation

the distance between the lens and the image sensor when the lens is focus at infinity

focal length