The invention relates to a measurement system (1) for optically measuring an object (2), comprising a dental camera (5) and an optical attachment (6). The optical attachment (6) comprises at least one lens (7, 8), which is shaped and arranged in such a way that the optical attachment (6) has a negative focal length such that a measurement field or a measurement volume (9) of the dental camera (5) is enlarged by the optical attachment (6).