Scanning unit for a position measuring device for optically scanning a material measure comprising - a light source for emitting light in the direction of a material measure, - a detector for receiving the light modified by the material measure, and - a lens arrangement (3, 4) arranged upstream of the detector and having a plurality of optical lenses and serving for generating a defined image of a region of the material measure that is scanned by means of the light on the detector, wherein the imagine scale (β) of the lens arrangement (3, 4) is greater than zero and less than or equal to two and the lens arrangement (3, 4) comprises two groups (3; 4) of lenses which are arranged in respectively one of two planes (30, 40) extended parallel to one another, wherein the planes (30, 40) are aligned in such a way that the modified light intersects the planes (30, 40) and the lenses of the two groups (3, 4) are respectively combined in pairs to form a cell (31a, 41a; 31b, 41b; 31c, 41c) and that the lenses (31a, 41a; 31b, 41b; 31c, 41c) of a cell are arranged one behind another in each case perpendicularly to the two planes (30, 40), such that at least one portion of the modified light rays which have passed through a first lens (31a, 31b, 31c) of a cell (31a, 41a; 31b, 41b; 31c, 41c) subsequently pass to the second lens (41a, 41b, 41c) of the cell (31a, 41a; 31b, 41b; 31c, 41c), characterized in that - the absolute value of the imaging scale (β1) of the first lens (31a, 31b, 31c) of the respective cell (31a, 41a; 31b, 41b; 31c, 41c) is less than the absolute value of the imaging scale (β2) of the second lens (41a, 41b, 41c) by an amount such that the light rays of a light beam which has passed through the first lens (31a, 31b, 31c) of one cell (31a, 41a; 31b, 41b; 31c, 41c) do not pass to a second lens (41a, 41b, 41c) of another cell (31a, 41a; 31b, 41b; 31c, 41c), and - the focal lengths (f1, f2) of the lenses (31, 32, 33; 41) of the first group and of the second group are different, wherein the focal length of the lenses (31a, 31b, 31c) through which the modified light passes first is preferably greater than the focal length of the other lenses (41a, 41b, 41c). - a light source for emitting light in the direction of a material measure, - a detector for receiving the light modified by the material measure, and - a lens arrangement (3, 4) arranged upstream of the detector and having a plurality of optical lenses and serving for generating a defined image of a region of the material measure that is scanned by means of the light on the detector, wherein the imagine scale (β) of the lens arrangement (3, 4) is greater than zero and less than or equal to two and the lens arrangement (3, 4) comprises two groups (3; 4) of lenses which are arranged in respectively one of two planes (30, 40) extended parallel to one another, wherein the planes (30, 40) are aligned in such a way that the modified light intersects the planes (30, 40) and the lenses of the two groups (3, 4) are respectively combined in pairs to form a cell (31a, 41a; 31b, 41b; 31c, 41c) and that the lenses (31a, 41a; 31b, 41b; 31c, 41c) of a cell are arranged one behind another in each case perpendicularly to the two planes (30, 40), such that at least one portion of the modified light rays which have passed through a first lens (31a, 31b, 31c) of a cell (31a, 41a; 31b, 41b; 31c, 41c) subsequently pass to the second lens (41a, 41b, 41c) of the cell (31a, 41a; 31b, 41b; 31c, 41c), characterized in that - the absolute value of the imaging scale (β1) of the first lens (31a, 31b, 31c) of the respective cell (31a, 41a; 31b, 41b; 31c, 41c) is less than the absolute value of the imaging scale (β2) of the second lens (41a, 41b, 41c) by an amount such that the light rays of a light beam which has passed through the first lens (31a, 31b, 31c) of one cell (31a, 41a; 31b, 41b; 31c, 41c) do not pass to a second lens (41a, 41b, 41c) of another cell (31a, 41a; 31b, 41b; 31c, 41c), and - the focal lengths (f1, f2) of the lenses (31, 32, 33; 41) of the first group and of the second group are different, wherein the focal length of the lenses (31a, 31b, 31c) through which the modified light passes first is preferably greater than the focal length of the other lenses (41a, 41b, 41c).