DSLR Camera

Overview

A digital single-lens reflex camera routes the image from a single taking lens through a moving mirror to an optical viewfinder, so the photographer composes through the exact optics that will expose the sensor. Pressing the shutter flips the mirror up, opens a mechanical focal-plane shutter, and exposes a digital image sensor. The reflex mirror box and pentaprism are what distinguish a DSLR from mirrorless cameras, giving a lag-free optical view at the cost of bulk and mechanical complexity.

How it works

Light enters through the lens and strikes the Mirror Box: the main reflex mirror reflects most of it up through a focusing screen and pentaprism to the Optical Viewfinder, while a sub-mirror passes a portion down to the Autofocus Module for phase-detect focusing. At exposure the mirror swings up, the Focal-Plane Shutter runs its front and rear curtains across the frame to time the exposure precisely, and light reaches the Image Sensor Module, a CMOS sensor behind an IR/anti-alias filter with ultrasonic dust shaking.

The Main Processor Board carries the image-processor SoC that demosaics, denoises, and compresses each capture into the buffer before writing it to the memory card. The whole mechanism is built on a Body Chassis of magnesium and polycarbonate with a moulded grip, and lenses attach through the Lens Mount, a bayonet ring whose electrical contacts pass focus and aperture commands to the lens.

The camera ships with a Kit Zoom Lens, an 18–55 mm stabilised zoom containing its own focus, zoom, aperture, and image-stabilisation groups driven by a lens CPU board. Controls, a pop-up flash, a rear touchscreen, a top status LCD, and I/O ports round out the body, making a self-contained system camera that accepts the full range of mount-compatible optics.