What is a Mirrorless Camera? While a DSLR camera uses a mirror mechanism to either reflect light into an optical viewfinder, or pass it through directly to the camera sensor, a mirrorless camera completely lacks such mirror mechanism (hence the name), which means that the light passing through the lens always ends up on the imaging sensor. Since light is no longer reflected on an optical viewfinder (OVF), mirrorless cameras typically rely on electronic viewfinders (EVF) and LCDs that basically project what the imaging sensor sees. Because of lack of a mirror mechanism and an optical viewfinder, mirrorless cameras can be made simpler, lighter and less bulky when compared to DSLR cameras. when compared to a mirrorless camera, a DLSR has a lot more components that make up the internals of the camera. Aside from the complex mirror mechanism, there is a focusing screen, a condenser lens, pentaprism / pentamirror and other components such as a secondary mirror and a phase-detection autofocus sensor that are present on a DSLR. How Mirrorless Cameras Work In contrast, a mirrorless camera is much simpler mechanically – light passes through the lens directly onto the image sensor and the optical viewfinder is replaced with an electronic viewfinder that replicates the image sensor. In normal operation, the mechanical camera shutter stays open and is only typically utilized at the end of exposure. Due to lack of both mirror and pentaprism, the flange distance (which is the distance between the lens mount and the image sensor) on mirrorless cameras can be shortened significantly, as the illustration above shows. Because of this, most mirrorless camera bodies are thinner and lighter compared to DSLRs.
