The Pentax ist DL is a 2004 entry-level digital single lens-reflex camera. A single-lens reflex (SLR) camera is a camera that typically uses a semi-automatic moving mirror system (hence the name "reflex", from the mirror's reflection) that permits the photographer to see exactly what will be captured by the film or digital imaging system, as opposed to pre-SLR cameras where the view through the viewfinder could be significantly different from what was captured on film.