Lamp with translucent piston tube

A lamp (1) has a light-transmitting piston tube (3), at least one in the piston tube (3) accommodated carrier board (2) to whose front face (4) at least one light source (5) and a partial inner side (on the piston tube 3 )-fitting, longitudinally open, light-transmitting sheet (9), in particular diffuser film, with two longitudinal edges, which foil (9) arches over the front side (4) of the support plate (2), wherein the film (9) located on the support plate (2 ) is supported resiliently. The invention is for example applicable to retrofit with at least one semiconductor light source, in particular for the replacement of tubular lamps such as fluorescent lamps, fluorescent lamps, lamps, etc. line