Optical path length adjustment

A system for adjusting an optical path length includes: a camera body; an image sensor coupled to the camera body; a first optical device coupled to the camera body; and a second optical device coupled to the camera body. At least one of the first and the second optical devices are movable relative to the camera body. The optical path length between the image sensor and the camera body opening is continuously adjusted by movement of the at least one of the first and the second optical devices relative to the image sensor. As the at least one of the first and the second optical devices move relative to the image sensor, the first optical device is in continuous contact with the second optical device.