Optisches Gerät mit einem Zoom-Linsensystem

摘要

The optical apparatus has a pair of relatively movable lens groups which are disposed on the common axis and a light intercepting member secured to and between the two lens groups. The light intercepting member is a thin, relatively long rectangular strip which is helically wound to form a plurality of coils. In an expanded state, the coils are overlapped to prevent incident light from passing into a space between the lens groups. At the same time, the strip is elastically resilient as to maintain the spacing between the two lens groups.