A position-determination system for an elevator uses a camera arranged on an elevator car, which camera has a sensor with a defined number of light-sensitive pixels for generating image data of a surface structure of hoistway material arranged along a travel path of the elevator car. An analysis unit, based on the image data, determines a position and/or velocity of the elevator car. The position-determination system recognizes a reference pattern with a specified dimension which lies in a capturing range of the camera, wherein, based on the reference pattern, the analysis unit performs a scaling of the image data.