Eccentricity-prevention mechanism for a pair of lens-supporting rings

摘要: An eccentricity-prevention mechanism includes a pair of lens-supporting rings for supporting lens groups, respectively; and positioning recesses follower projection formed on one the other opposed surfaces rings, such that engages with recess to define relative position respect optical axis, at mutually close distant position. At least three pairs projections are provided different positions in circumferential direction, so eccentricity between is eliminated when all concurrently brought into engagement corresponding recesses.