| 摘要 |
An adjustment device for a macrolens objective wherein a first lens group and a second lens group are axially displaceable is constructed so that the rotary movement necessary to move the second lens group in an axial direction is derived from the axial movement of the first lens group. There is no direct connection between the first lens holder and a stationary housing. The first lens group holder is threadably attached to the focusing ring which in turn is threadably attached to the lens housing by threads of equal but opposite pitch. The axial movement of the first lens holder is transmitted to the second lens holder, preferably, by an intermediate ring having internally threaded helical grooves. The first lens holder is engaged in the helical grooves of the intermediate ring, which ring in turn is engaged in internally threaded helical grooves of the same pitch of a cylindrical portion of the second lens holder. The rotary movement of the cylindrical portion causes the second lens holder to move axially relative to the lens housing to which it is threadably engaged.
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