Abstract: A retaining device includes a body portion and at least two legs extending from the body portion. The device further includes a construction for securing the retaining device such that the yield point of the material forming the retaining device must be exceeded in order to achieve operative release of this securing construction. In preferred embodiments, the retaining device is formed from a spring metal material having a round cross section.

Abstract: In a lens system including a thermal compensation mechanism that compensates for unwanted positional shifts between two tenses in the lens system resulting from changes in a temperature of the lens system, a bias mechanism is provided to bias elements of the lens system together. The bias force exerted by the bias mechanism on the thermal compensation mechanism insulates the lenses from effects of a dynamic environment, and ensures that a distance between the lenses along the optical axis will change with temperature of the lens system to provide necessary compensation. In an exemplary embodiment, the bias mechanism is a cylinder with a helical cut along its length that laterally surrounds a portion of the compensation mechanism, and provides a bias force in a direction parallel to the optical axis to urge angled interfaces of the compensation mechanism into abutment.