In a zoom lens (30) comprising, from the object side to the image side, a front lens group (12) and a controllable lens group (24), the controllable lens group comprises two lens elements (25, 26) having different dispersions and being movable with respect to each other so as to perform a focusing action. One of the lens elements corrects for the dispersion of the zoom lens. Preferably, the zoom lens comprises at least one folding mirror.


> Zoom lens system

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