Patent ID: 6253033
Filing Date: 2001-06-26
Classification: G02B,G03B

Abstract:
An eyepiece optical system for a single lens reflex camera having a penta mirror, comprising:a negative first lens group, a positive second lens group, and a negative third lens group, in this order from said penta mirror;wherein said second lens group is a diopter adjusting lens group which is adjustable along the optical axis; andwherein said eyepiece optical system satisfies the following conditions:-0.8<f.sub.1G /f.sub.e <-0.20.2<f.sub.2G /f.sub.e <0.5-15<f.sub.3G /f.sub.e <-1whereinf.sub.1G designates the focal length of said first lens group;f.sub.2G designates the focal length of said second lens group;f.sub.3G designates the focal length of said third lens group; andf.sub.e designates the focal length of the entire eyepiece optical system when the diopter is -1.0.