DSLR stands for Digital Single Lens Reflex, and it is a type of digital camera. These cameras can be expensive and are the type used by most professional photographers. They get their name from their unique viewing system, in which a mirror reflects light from the lens through a separate optical viewfinder. At the moment of exposure, the mirror flips out of the way, making a distinctive "clack"sound and allowing light to fall on the image sensor. This system allows you to see through the viewfinder exactly what your finished shot will look like, or WYSIWYG (what you see is what you get).