A method for refinishing a surface structure of shaft material of an elevator, which extends along a shaft, enables the use of image data to determine an absolute position and/or speed of an elevator car. The elevator includes the elevator car, which is movable in the shaft, a camera, which is arranged at the elevator car and generates the image data from the surface structure, and an evaluating unit, which determines the absolute position and/or the speed of the elevator car from the image data. The surface structure is refinished at least locally in order to increase a distinctiveness of the surface structure in the image data. The shaft material can be, for example, a guide rail, a fastening element of the guide rail, or a shaft wall.