Upon entering the market in 1976, the K1000 wasn't the revolutionary kind of camera that left photography enthusiasts breathless. It didn't have a single program mode and lacked a depth-of-field preview function. What it did have, however, was an uncluttered design that made it easy to use, practical and economical. This was enough to keep it in production until 1997 and make it the go-to entry-level SLR for students. The K1000 sold over 3 million units during its 21-year run.