Macrolens system for cameras comprises first and third positive lens groups and interposed second and fourth negative lens groups with conditions describing lens travel from infinity to near settings.

摘要

Viewed from the subject side, the macrolens system consists of a first positive lens group (10), a second negative lens group (20) and positive third (30) and negative fourth (40) lens groups and in sharp focusing, commencing from infinity focus right through to the close-up limit, the second lens group (20) is moved towards the image and the third group (30) moved towards the subject. This should satisfy the condition (lf . m/ delta X3l to lie between 3.7 and 9.9) wherein (f) denotes the total focal length in the infinity setting with image scale at near focus limit and ( delta X3) is the travel by the third lens group (30) from infinity to near focus setting. In addition to this, the system satisfies the condition (l delta X3/ delta X2l between 0.85 and 1.5) in which ( delta X2) represents the path traveled by the second lens group (20) from infinity to near focus setting. In a third condition (l beta 3E- beta 3sl) should be between 0.1 and 0.34, with ( beta 3E/ beta 3s to be up to 0). The image scale of the third lens group (30) in infinity setting is denoted by ( beta 3E) and ( beta 3s) is the third lens group image scale in the near focus setting.