INNER FOCUS TYPE MACRO LENS HAVING VIBRATION-PROOF FUNCTION

• Main Author: SHIODA RYO
• Format: Patent
• Language: English
• Published: 20.01.2011
• Subjects: ACCESSORIES THEREFOR; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USINGWAVES OTHER THAN OPTICAL WAVES; APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FORPROJECTING OR VIEWING THEM; CINEMATOGRAPHY; ELECTROGRAPHY; HOLOGRAPHY; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHOTOGRAPHY; PHYSICS

PROBLEM TO BE SOLVED: To provide an inner focus type macro lens having a vibration-proof function for correcting displacement of an imaging position due to camera shake or the like, which achieves photography from an infinity object to a short distance object near unmagnification.SOLUTION: The inner focus type macro lens having the vibration-proof function has, in order from an object side: a first lens group L1 having positive refractive power; a second lens group L2 having negative refractive power; a third lens group L3 having positive refractive power; and a fourth lens group L4 having negative refractive power. When focusing from the infinity object to the short distance object, the second lens group L2 is moved in an optional direction as soon as at least the third lens group L3 is moved to the object side, so as to perform short distance photography near to the unmagnification. The fourth lens group includes a front group having negative refractive power, and a rear group having positive refractive power, wherein image blur is corrected by moving the front group in a direction nearly perpendicular to an optical axis when the optical system is vibrated. The inner focus type macro lens satisfies a predetermined conditional expression.