| 摘要 |
A relay variable magnification optical system is provided with a variable magnification optical system that receives light from a primary image to carry out the variation in the magnification of a secondary image, and a rear lens group that receives the light passing through the variable magnification optical system to form the secondary image. The variable magnification optical system is comprised of a first lens group (G1) with positive refracting power, a second lens group (G2) with negative refracting power, a third lens group (G4) with positive refracting power, and a fourth lens group (G5) with positive refracting power in that order from the secondary image side. The relay variable magnification optical system is characterized in that, when magnification is varied from a higher magnification edge state to a lower magnification edge state, the fourth lens group (G4) moves to the secondary image side, a gap between the first lens group (G1) and the second lens group (G2) increases, positions of the primary and secondary images and those of an entrance pupil of the relay variable magnification optical system, a pupil of the variable magnification optical system and an exit pupil of the relay variable magnification optical system are kept substantially constant, and the pupil of the variable magnification optical system is in a position closer to a side of the secondary image than the end surface of the variable magnification optical system |
