Lens system for e.g. camera, has lens unit with negative refraction power having flat concave lens, and other lens units with positive refraction power are displaced in opposite directions to pass from one position to another

摘要

The system (100) has a lens unit (110) with a positive refraction power and an opening (120) to let light pass through. Other lens units (130, 140) have positive and negative refraction powers, respectively, where the lens units are constructed in a single block. The unit (140) with flat concave lens (141) having flat surface is fixed and the units (110, 130) are positioned selectively in two positions, where the units (110, 130) are displaced in opposite directions to pass from one position to another.