Compact lens systems that may be used in small form factor cameras. The lens system may include a master lens with two or more lens elements arranged along an optical axis and having refractive power, and an optical actuator located on the object side of the master lens that may provide autofocus (AF) and/or optical image stabilization (OIS) functionality for the camera. An aperture stop for the camera may be included in the optical actuator, for example between a substrate and a flexible optical element of the optical actuator. Including the aperture stop in the optical actuator rather than in the lens stack may allow the optical actuator to be smaller in the X-Y dimensions (perpendicular to the optical (Z) axis) than it would be in a similar camera with the aperture stop located in the lens stack.