FIELD: optics. SUBSTANCE: variolens with final distance from object plane to image plane by each of two implementation variants has three axially mobile components. First and third components are positive and second component is negative. First and third components are mounted for their joint displacement with maintenance of constant distance between them. Distance L1+D1act measured from first component to object plane changes by value D1act within limits from 0 to D1max. In case of first variant change of distance D2act between second component and object plane depends on setting for sharpness while distance between second and third components remains invariable. According to second variant distance D2act between second component and object plane is changed forcibly and non-linearly. EFFECT: simplified design with simultaneous reduction of fluctuation of focus, including great distances from object plane to image plane and large magnification intervals. 18 cl, 3 dwg, 1 tbl
