IMAGING OPTICAL SYSTEM, AND DIGITAL STILL CAMERA USING IT, VIDEO CAMERA AND MOBILE EQUIPMENT USING SAME

PROBLEM TO BE SOLVED: To obtain a small-sized and high-resolution imaging optical system which is thin, but tolerant of temperature variation. SOLUTION: A 1st lens group 11 and a 2nd lens group 12 are arranged in order from an object side to an image plane side. The 1st lens group 11 is composed of a 1st meniscus lens L1 which is convex to the object side and has positive refracting power, and at least one surface of it is aspherical. The 2nd lens group 12 is composed of a 2nd lens L2 which is concave to the object side and has negative refracting power and at least one surface of it is aspherical. Here, the optical system satisfies conditional inequalities of [32 number] 0.7