| 摘要 |
PROBLEM TO BE SOLVED: To enable downsizing of a vibration isolating correction lens and consequently to enable the reduction of the weight and size over the entire part by constituting a vibration isolating observation optical system so as to satisfy specific conditions. SOLUTION: This vibration isolating observation optical system, which includes a vibration isolating correction lens driven in a direction orthogonal to the optical axis in an object optical system I, is constituted by providing this optical system successively from an object side, with the object optical system I, an erecting optical system P and an eyepiece optical system II. Such an optical system is made to satisfy the conditional equation, 1 mm<=ϕ-ϕ0<=3 mm where,ϕis the mechanical outside diameter of the vibration isolating correction lens, andϕ0 is the axial open value of the first face of the vibration isolating correction lens. Namely, if the mechanical outside diameter of the vibration isolating correction lens is set from the axial open diameter in the zero state of the eccentricity quantity of the correction lens, the vibration isolating correction lens can be made small in diameter and thin, and is consequently made lighter. However, even if the exit diameter charges when the correction lens is offcentered, degradations detrimental in does not occur practice to an observer. The conditional equation regulates the diameter (mechanical outside diameter) of the vibration isolating correction lens according to such a notice.
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