There’s a new breed of camera making rapid inroads in photography. Known as MILCs (mirrorless interchangeable lens cameras) or simply mirrorless cameras, these bodies are much smaller than those of DSLRs- they weigh in between point-and-shoots and small DSLRs.
The size reduction is possible because the mirror of the DSLR, which angles light to the pentaprism and then to the viewfinder, is missing. Instead, a large, usually 3” LCD screen, replaces the viewfinder (some have an electronic viewfinder, sometimes as an option). The loss of the mirror reduces the size of the camera body, minimizes the time required between exposures (since there’s no mechanical mirror to be flipping up and down), and reduces the noise of activating the shutter.
The result is a small camera body as well as a line of lenses that are less expensive and lighter. The DSLR camera bag is replaced by little more than a pouch to store gear.
Image quality is impressive in most.
Only one MILC utilizes a full frame sensor- the size found on professional DSLRs. Sony utilizes the same sensor size found in nearly all DSLRs, sometimes known as Dx. The majority of these cameras use what is known as a four thirds sensor (due to its 4:3 aspect ratio). These sensors are smaller than the Dx sensors, but larger than the smallest of the MILC sensors found in the Nikon 1 System. Sensor size will relate to image quality and depth of field. A drawback to the small sensors is a large depth of field- backgrounds tend to stay in focus. The soft blurring of the background, known an bokeh, which is so important in portraiture, is much harder to achieve with these cameras.
But despite some challenges, it appears that MILCs are here to stay and will be improving greatly in the next few years. If you’re looking to get into a mirrorless system, look into the Sony NEX, Nikon 1, Olympus E or the Panasonic G lines.