| 摘要 |
A lens barrel has its collapsed length that can be further decreased by removing unnecessary space and bringing lens groups close to each other and a photographic apparatus incorporates the lens barrel. When the lens barrel is collapsed, at least a fourth lens group is retracted from a photographic optical axis by an advance/retract mechanism. In that case, a first lens group and third lens group are aligned along the optical axis and stuffed into the lens barrel, the fourth lens group is placed on the top, bottom, right, or left side of these lenses, and a second lens group is placed on the top, bottom, right, or left side of the first and third lens groups. This reduces the length of the lens barrel. During extension, the second and fourth lens groups are advanced onto the photographic optical axis by the advance/retract mechanism to extend the lens barrel greatly.
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