Lighting unit for use in a luminaire , in particular in a luminaire for road and/or street lighting, wherein said lighting unit comprises an LED light source and a primary optics formed by a lens , wherein said lens comprises a light entry region formed by a cavity , at least a light emitting portion of the LED light source being arranged within said cavity , wherein the size of the cavity of the lens exceeds the size of the LED light source allowing multiple positioning of the LED light source within the cavity , and wherein a distribution of light emitted by the lens depends on the positioning of the LED light source (30, 30-1, 30-2) within the cavity , wherein the cavity of the lens has a longitudinal shape, wherein the extension of an illuminated area in a direction perpendicular and in a direction parallel to the longitudinal direction (I) of the cavity depends on the positioning of the LED light source (30, 30-1, 30-2) within the cavity , whereas said lens - independent from the positioning of an LED light source (30, 30-1, 30-2) - provides a symmetric light distribution in the direction perpendicular to the longitudinal direction (I) of the cavity and an asymmetric light distribution in the direction parallel to the longitudinal direction (I) of the cavity , characterized in that shifting the position of the LED light source (30, 30-1, 30-2) within the cavity slightly adapts the asymmetric light distribution in the direction parallel to the longitudinal direction (I) of the cavity and has a much stronger effect on the extension of the illuminated area in the direction perpendicular to the longitudinal direction (I) of the cavity . wherein said lighting unit comprises an LED light source and a primary optics formed by a lens , wherein said lens comprises a light entry region formed by a cavity , at least a light emitting portion of the LED light source being arranged within said cavity , wherein the size of the cavity of the lens exceeds the size of the LED light source allowing multiple positioning of the LED light source within the cavity , and wherein a distribution of light emitted by the lens depends on the positioning of the LED light source (30, 30-1, 30-2) within the cavity , wherein the cavity of the lens has a longitudinal shape, wherein the extension of an illuminated area in a direction perpendicular and in a direction parallel to the longitudinal direction (I) of the cavity depends on the positioning of the LED light source (30, 30-1, 30-2) within the cavity , whereas said lens - independent from the positioning of an LED light source (30, 30-1, 30-2) - provides a symmetric light distribution in the direction perpendicular to the longitudinal direction (I) of the cavity and an asymmetric light distribution in the direction parallel to the longitudinal direction (I) of the cavity , characterized in that shifting the position of the LED light source (30, 30-1, 30-2) within the cavity slightly adapts the asymmetric light distribution in the direction parallel to the longitudinal direction (I) of the cavity and has a much stronger effect on the extension of the illuminated area in the direction perpendicular to the longitudinal direction (I) of the cavity . <EOS>