Abstract: Systems and methods configured for outputting light having a polarization state distribution that is spatially uniform by applying a correction to, for example, a beam of light with a spatially uniform polarization state distribution that has been altered (unintentionally or otherwise) to become spatially non-uniform are described. A projection system can include an optical element and a polarization-altering device (PAD). The optical element can cause a polarization of light in the projection system to be spatially non-uniform. The PAD can change the polarization state distribution of the light spatially based on an amount of spatial non-uniformity on the light caused by the optical element and before the light enters the optical element. The projection system can output the light having a spatially uniform polarization state distribution.

Abstract: A rifle scope has a body with a number of optical elements. An adjustment knob is rotated we connected to the body and interacts with at least one of the optical elements to provide an image shift in response to rotation of the knob. A detent mechanism interacts with the knob, and has a number of detent positions. Many of the detent positions have a first detent force, and a selected subset the detent positions have a greater second force. The selected subset of detent positions may correspond to selected major distance intervals.