3.1 Basics of digital photography

Digital photography is the capture of images with an electronic image sensor that converts light into digital data, which is stored as a file on a memory card or in a phone's memory. A photojournalist must understand how the camera controls light, focus and colour, because these decide whether a news picture is sharp, correctly exposed and true to the scene. Mastering the basics allows the photographer to work quickly in changing conditions without losing the moment. Example: a photographer for a regional weekly in Kapedo switched from automatic to manual exposure to capture a dusty livestock market in harsh midday light without losing detail in the shadows.

How a digital camera works

1. Light enters the lens: The lens gathers light from the scene and focuses it.
2. The aperture controls the amount of light: An adjustable opening in the lens lets in more or less light.
3. The shutter controls the time: The shutter opens for a set time to let light reach the sensor.
4. The sensor records the light: Millions of light-sensitive points (pixels) on the sensor measure brightness and colour.
5. The processor builds the image: The camera's processor turns the sensor data into an image, applying white balance, sharpening and compression.
6. The file is stored: The image is saved to the memory card as a JPEG, a raw file or both.

The exposure triangle

Exposure is the amount of light that reaches the sensor. It is controlled by three settings that work together: changing one requires adjusting another to keep the same brightness.

• Aperture: The size of the lens opening, given as an f-number such as f/2.8 or f/16. A small f-number means a wide opening, more light and a shallow depth of field (a blurred background); a large f-number means a narrow opening, less light and more of the scene in focus.
• Shutter speed: How long the shutter stays open, such as 1/1000 second or 1/30 second. Fast speeds freeze action; slow speeds let in more light but show movement as blur and need a steady camera.
• ISO: The sensitivity of the sensor, such as ISO 100 or ISO 3200. Higher ISO allows shooting in dim light but adds noise (grain) and reduces detail.

Other key camera settings

• Shooting modes: Automatic; programme (P); aperture priority (A or Av), where the photographer sets the aperture; shutter priority (S or Tv), where the photographer sets the shutter speed; and manual (M), where both are set.
• Metering: How the camera measures light: evaluative or matrix (whole frame), centre-weighted and spot (a small area, useful for a backlit face).
• Exposure compensation: Making the camera's chosen exposure brighter or darker, written as plus or minus EV values.
• Focus modes: Single autofocus for still subjects, continuous autofocus for moving subjects, and manual focus for difficult conditions.
• White balance: Adjusts colour so that white objects look white under daylight, shade, tungsten or fluorescent light.
• Drive mode: Single shot or continuous (burst) shooting for fast action.

Image file formats

Resolution and image quality

• Megapixels: The number of pixels in millions. More megapixels allow larger prints and more cropping, but sensor size and lens quality matter as much.
• Sensor size: Larger sensors, such as full frame, gather more light and give cleaner pictures in low light than small phone sensors.
• Focal length: Measured in millimetres. Wide-angle lenses (for example 24 mm) show more of the scene; telephoto lenses (for example 200 mm) bring distant subjects closer.

Types of cameras used in photojournalism

• Mirrorless cameras: Compact interchangeable-lens cameras with electronic viewfinders, now the standard for many news photographers.
• DSLR cameras: Interchangeable-lens cameras with an optical viewfinder, still widely used.
• Smartphones: Increasingly used for news, especially breaking events and social media.
• Compact cameras: Small cameras with fixed lenses, useful as a discreet back-up.