| 摘要 |
PROBLEM TO BE SOLVED: To provide a retro focus type lens having high optical performance favorable for a liquid crystal projector. SOLUTION: This retro focus type lens for projecting magnifingly an image of a display surface on a screen has, in order from a screen side, the first lens group L1 having negative refractive power, a diaphragm, and the second lens group L2 having positive refractive power. The first lens group L1 has a positive lens having a convex face in a screen side, and a meniscus-shaped negative lens having a convex face in the screen side in order from the nearmost side to a screen, and a conditional expression 2.0<bf/f is satisfied in the retro focus type lens, where (bf) represents a backfocus of an air-equivalent length and (f) is a focal distance of the whole system.
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