Fundamentals of Photography PDF

Forensic Photography  Photography A picture is worth a thousand words. It is the art, science and practice of capturing light to create images on a light-sensitive medium. Etymology – PHOTOS : Light – GRAPHOS : Pertaining to drawing or writing  Photogr...

Forensic Photography  Photography A picture is worth a thousand words. It is the art, science and practice of capturing light to create images on a light-sensitive medium. Etymology – PHOTOS : Light – GRAPHOS : Pertaining to drawing or writing  Photography Automatic Photography Manual Photography Technical Photography – Correct exposure – Maximum depth of field – Free from distortion – Sharp focus  Basic Principles Light Exposure Essential for capturing an image. Refers to the amount of light that reaches Understanding light sources and their the camera sensor or film. Proper qualities (intensity, direction, and color) is exposure ensures the image is neither too crucial. bright (overexposed) nor too dark (underexposed).  contd… Electromagnetic energy with wavelengths within the range of 400 to 700 nm is capable of stimulating receptors (rods and cones) in the retina Light Sources The Photographic Triangle  Stop…!!!! In Photography, Stop refers to the doubling or halving of the amount of light that makes up an exposure. – Adding stop: Brighten the underexposed – Decreasing stop: Darken the overexposed  Shutter Speed It is basically the length of time, light is allowed to hit the sensor  Aperture i.e. if we half the area of opening, we Size of the circular hole in eventually half the light hitting the sensor thereby decreasing the exposure by one the lens that lets in light. stop. f-stop : focal length/diameter (Size of that opening)  As from formula, large f-stop numbers refer to small openings and vice versa  ISO Sensitivity of digital sensor. – Higher values of ISO mean that the sensor does not need to collect as much light to make a correct exposure.  Depth of field The range of distance within a photo that appears sharp. Controlled by aperture – i.e. Larger the aperture or smaller the f-stop number, Shallower the depth. – Vice versa Basic TECHNIQUES  Rule of Thirds Divides the image into nine equal parts by two equally spaced horizontal lines and two equally spaced vertical lines. Place important elements along these lines or their intersections.  Leading lines Use natural lines in the scene to lead the viewer’s eye towards the main subject.  Framing Use elements within the scene to frame the subject, drawing attention to it.  Focus and Exposure Manual Focus: Allows precise control over what is in focus Automatic Focus: Camera’s autofocus system adjusts the focus automatically based on the subject Exposure Control: Use manual settings to control exposure or rely on the camera’s metering system to automatically adjust. EXPOSING, DEVELOPING, AND PRINTING  Exposure Tools Exposure Triangle Light Meter: Measures the amount of light and suggests appropriate settings. Histogram: A graphical representation of the exposure levels in an image. Ensure data is spread evenly without clipping shadows or highlights.  Developing Traditional Film Development: – Process Overview: Involves chemical treatments to convert exposed film into visible images. Key stages include developing, stopping, fixing, and washing. – Developing Solutions: Chemicals used to develop film and create negatives.  Developing Digital Development: – Basics: Involves converting digital files into final images using software. – Editing: Basic adjustments like cropping, color correction, and exposure adjustments. Advanced techniques may include noise reduction and sharpening.  Printing Types of Prints: Traditional Photo Paper: Uses chemical processes for printing. Digital Prints: Produced using inkjet or laser printers, offering more flexibility and faster results.  Printing Techniques: – Color Management: Ensures colors are reproduced accurately in prints. – Resolution: Higher resolution (e.g., 300 DPI) ensures clearer prints. MODERN DEVELOPMENTS IN PHOTOGRAPHY  Advancements in Technology High-Resolution Cameras: Allow for detailed imaging, which is crucial for forensic evidence. Specialized Equipment: – Macro Lenses: For capturing fine details. – Infrared Photography: Used to reveal details not visible in standard images.  Software and Tools Editing Software: – Popular Programs: Adobe Photoshop, Lightroom, GIMP. – Applications: For adjusting exposure, contrast, and correcting distortions. Digital Enhancement: – Techniques: Sharpening, noise reduction, and color correction to enhance image clarity and detail.  Emerging Trends 3D Photography: Automated Systems: Applications: Creating three-dimensional Drones: For capturing aerial images of models of crime scenes or objects. crime scenes. Techniques: Use of specialized cameras or Automated Imaging: Systems for software to stitch together multiple continuous capture and analysis. images. DIGITAL PHOTOGRAPHY  Basics of Digital Photography Digital Sensors: – CCD vs. CMOS: CCD (Charged Coupled Device) sensors offer high-quality images but are slower, while CMOS (Complementary Metal-Oxide-Semiconductor) sensors are faster and use less power. – Impact on Image Quality: Sensor size and resolution.  CCD CMOS Global Shutter (captures all Rolling Shutter (exposes the light at nearly the same time) frame from top to bottom)  Basics of Digital Photography File Formats: – JPEG: Compressed format, good for general use but with some loss of detail. – RAW: Uncompressed format, retains more image detail and allows extensive post-processing. Digital Storage and Management Data Integrity: Importance of maintaining original, unaltered files for forensic evidence. File Organization: Best practices for archiving and retrieving images, such as using consistent naming conventions and metadata.  Basics of Videography Principles of Motion Capture: – Frame Rates: Standard rates (24, 30, 60 FPS) and their impact on motion portrayal. – Resolution: High-definition vs. standard-definition video. Differences from Still Photography: Continuous capture versus single frames, the role of motion blur.  Why Video…..? Isn’t photography sufficient Objective Reasons Unbiased Documentation It is running narrative of the sequential “walk through” of the scene. As such it presents objective facts, conditions and sequence that can followed as though walking through the scene personally. “Feel” Visual Proof of the crime Of the fire or other crime (Photography also provides this). Video provides the same information but in a “live” format. Such as seeing the flame moves in a fire. Testimony Use the video as demonstrative evidence for the jury which presents the scene in a better-to-view format that is almost “live” Refresh Memory Long delays between crime and courtroom can change or dull the crime scene details.  High-Speed Videography Recording an event at a high frame rate and playing the images back at a much slower rate Applications: – Capturing Fast Events: Useful for analyzing rapid movements or impacts. – Equipment: High-speed cameras with high frame rates (e.g., 1000 FPS or more). Techniques: – Lighting: High-speed videography often requires specialized lighting to ensure clarity. – Analysis: Frame-by-frame examination for detailed study.  Forensic Applications Ballistics – Bullet Trajectory – Gunshot Wound Blood Spatter Analysis Wildlife Forensics Forensic Ornithology Road Accidents