Canon's got a new 50mm F/1.8 Pancake STM Lens available. On Canon cameras the STM lenses are designed with stepper motors for quieter and faster full time autofocus in video mode, unlike your standard photo lenses.
I own both the 24mm STM Lens and the 40mm STM pancakes because I really like the compact size and super affordable cost. It's perfect for keeping the weight down when balancing a camera on small gimbal stabilizer. The new 50mm lens is an EF mount (not ef-s), so it will cover a full frame camera . If you are using a Sony, Panasonic, or BlackMagic camera body, you can add either a metabones lens adapter or the Aputure DEC to control focus and iris.
The new Canon 50mm F/1.8 STM Pancake style lens sells for just $125 (here).
One of the most versatile focal lengths available, the EF 50mm f/1.8 STM Lens from Canon pairs this classic lens design with enhancements to the AF system and physical design that make it both faster and smaller. Utilizing an STM stepping motor, this lens is ideal for both still and video shooting due to its speedy and smooth operation. Further benefitting video shooters, the STM motor also supports the Movie Servo AF mode on select DSLRs for precise and near-silent focusing. An updated exterior design includes a metal lens mount and a re-located focusing ring in order to accommodate the compact overall form factor. The 50mm f/1.8 is a classic, tested lens design, and thanks to enhanced autofocus and a svelte profile, this lens is ideal for everyday shooting in a wide variety of conditions.
Canon EF-S 24mm f/2.8 STM Lens