An optical sensing device for using light to locate objects or features in a field of view comprises a light source; a controllable lens having two states and being controllable between them, for example a multifocal lens having two or more foci for focusing light from the light source; and a sensor able to sense light reflected from an object, to determine information of the object. The use of two or more foci adds dynamic range to optical sensing to allow for reliable detection over a wide range of distances.