Many clients are more acquainted with digital compacts, since these models have flooded the marketplace. Like cell phones, it is tough to walk down the road nowadays without seeing somebody snapping a photo. Digital SLR cameras are even less common, and up till 2005 were truly only utilised by professional photographers.

Digital single-lens reflex cameras (DSLRs) are electronic cameras based primarily on film single-lens reflex cameras (SLRs). They take their name from their unique check out system, in which a mirror reflects light from the lens through a new optical rangefinder. To capture a photo the mirror is flipped out of the way, permitting light to fall on the imager. Since, without light reaching the imager during framing, auto-focus is accomplished using specialised sensors in the mirror box itself. Most 21st century DSLRs also have a "live view" mode that simulates the live preview system of compact cameras, when selected.

These cameras have much bigger sensors than the other types, generally 18 mm to 36 mm on the diagonal. This gives them superior low-light performance, not much depth of field at a given aperture, and a bigger size. They use interchangeable lenses; each chief DSLR manufacturer also sells a line of lenses in particular meant to be used on their cameras. This permits the user to choose a lens designed for the application to hand: wide angle, telephoto, low-light, and so on. So each lens doesn't need its own shutter, DSLRs use a focal-plane shutter in front of the imager, behind the mirror. The mirror flipping out of the way now of exposure makes a characteristic "clack" sound.