| 摘要 |
The invention is directed to an objective for telescope-type stereomicroscopes with magnification that can be adjusted at post-magnification systems. The objective, which comprises two lens groups LG1 and LG2, satisfies the two conditions DAP>=42 mm, and tan(omega)>=0.16, where DAP is the diameter of the exit pupil and omega is the field angle of the objective at the lowest possible magnification setting. When this condition is met, the optical axis of the objective lies midway between the center lines of the two post-magnification systems. In preferred constructions, the total focal length f'objective of the objective is between 40 mm and 160 mm, and the relationship of the focal length f'LG2 of the second lens group LG2 to the total focal length f'objective is expressed by 0.1-1.8723/f'objective<=1/f'LG2<=0.2-1.8723/f'objective.
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