Complete Comprehensive Notes on Forensic Photography
Introduction to Photography
The word photography comes from Greek, meaning "writing with light." Light travels from any source (sun, bulb) and reflects back to make objects visible. A camera lens refracts light rays to form an upside-down image.
Camera Basics
The term “camera” is derived from Camera Obscura, meaning “dark room,” where light passes through a hole, projecting an upside-down image.
- Modern cameras include optical (lens), chemical (film), and mechanical (camera body) elements.
Essential Parts of a Camera
- Aperture – Controls the amount of light entering the camera, measured in f-stops (e.g., f/2, f/4). It affects the depth of field, which determines how much of the image is in focus.
- Shutter Speed – Determines how long the sensor is exposed to light, controlling motion blur. It ranges from 1/4 to 1/4000 seconds.
- ISO Settings – Refers to the camera’s sensitivity to light, ranging from 100 to 6400 ISO (or higher).
Types of Lighting in Photography
- Natural Light: Using sunlight for photographs.
- Studio Light: Controlled artificial lighting in a studio.
- Key Light: The main source of light that defines the subject's tone.
- Fill Light: Complements the key light by reducing shadows.
Common Camera Types
- SLR Camera: Single-lens reflex cameras where the viewfinder shows exactly what the lens captures using a reflex mirror system.
- Digital Cameras (DSLR): Use electronic sensors to capture images and store them as digital files.
- Mirrorless Cameras: Do not use a reflex mirror, relying on an electronic viewfinder instead.
Exposure Triangle
The three components that control exposure in photography:
- Aperture: Controls light entry and depth of field.
- Shutter Speed: Controls light exposure time and motion blur.
- ISO: Adjusts sensor sensitivity to light.
Lens Types
- Prime Lenses: Fixed focal lengths, known for sharpness.
- Zoom Lenses: Variable focal lengths, offering flexibility but less speed.
- Macro Lenses: Ideal for close-up photography, allowing sharp, detailed images.
- Wide-Angle Lenses: Capture more of the scene, suitable for landscapes.
- Telephoto Lenses: Zoom in on distant subjects, used in wildlife and sports photography.
Light and Filters
- Light Source Characteristics: Strength, quality, and direction impact a photograph’s look.
- Filters: Attach to lenses to protect or alter exposure, contrast, and glare. Common types include UV, polarizing, and colored filters.
Crime Scene Photography
- Used to document evidence for court and investigations.
- Follow cardinal rules: fill the frame, maintain depth of field, and keep the film plane parallel for accurate representation.
