Photolithography apparatus comprising - a mask stage arranged for positioning a mask comprising a mask pattern for patterning an illumination beam according to the mask pattern; - a substrate stage arranged for positioning a substrate for receiving a substrate pattern onto the substrate; and - a projection system arranged for projecting an image of the mask pattern as the substrate pattern onto the substrate, wherein the projection system comprises ο an adjustment lens moveable in a range (Xmin,Xmax) encompassing a central position for controlling a relative image size (S1/S0) of the projected substrate pattern by a relative position of the adjustment lens; - the apparatus further comprising a controller configured to adjust the relative image size (S1/S0) of the projected substrate pattern by controlling the relative position of the adjustment lens; characterized in that the projection system is arranged to project the mask pattern onto the adjustment lens such that, when the adjustment lens is positioned at the central position, an apparent mask pattern (M') from a point of view of the adjustment lens appears to be at a distance (2*F) from the adjustment lens that is twice a focal length of the adjustment lens. - a mask stage arranged for positioning a mask comprising a mask pattern for patterning an illumination beam according to the mask pattern; - a substrate stage arranged for positioning a substrate for receiving a substrate pattern onto the substrate; and - a projection system arranged for projecting an image of the mask pattern as the substrate pattern onto the substrate, wherein the projection system comprises ο an adjustment lens moveable in a range (Xmin,Xmax) encompassing a central position for controlling a relative image size (S1/S0) of the projected substrate pattern by a relative position of the adjustment lens; - the apparatus further comprising a controller configured to adjust the relative image size (S1/S0) of the projected substrate pattern by controlling the relative position of the adjustment lens; characterized in that the projection system is arranged to project the mask pattern onto the adjustment lens such that, when the adjustment lens is positioned at the central position, an apparent mask pattern (M') from a point of view of the adjustment lens appears to be at a distance (2*F) from the adjustment lens that is twice a focal length of the adjustment lens. ο an adjustment lens moveable in a range (Xmin,Xmax) encompassing a central position for controlling a relative image size (S1/S0) of the projected substrate pattern by a relative position of the adjustment lens; - the apparatus further comprising a controller configured to adjust the relative image size (S1/S0) of the projected substrate pattern by controlling the relative position of the adjustment lens; characterized in that the projection system is arranged to project the mask pattern onto the adjustment lens such that, when the adjustment lens is positioned at the central position, an apparent mask pattern (M') from a point of view of the adjustment lens appears to be at a distance (2*F) from the adjustment lens that is twice a focal length of the adjustment lens. - the apparatus further comprising a controller configured to adjust the relative image size (S1/S0) of the projected substrate pattern by controlling the relative position of the adjustment lens; characterized in that the projection system is arranged to project the mask pattern onto the adjustment lens such that, when the adjustment lens is positioned at the central position, an apparent mask pattern (M') from a point of view of the adjustment lens appears to be at a distance (2*F) from the adjustment lens that is twice a focal length of the adjustment lens.