The invention relates to a system and to a corresponding method for optical coherence tomography having an interferometer (10) for emitting light with which a specimen (1) is irradiated, the interferometer (10) comprising a beam splitter (13) and at least one reflector (12) the optical distance (I) of which from the beam splitter (13) can be changed by an optical path (L), and a detector (30) with a first number of detector elements arranged in a first area for collecting light which is reflected by the specimen (1).In order to be able to record images of a specimen, in particular in real time, more simply and quickly, the system is operated in a first mode in which light reflected by the specimen (1) is only collected by a second number of detector elements of the detector (30) and converted into corresponding detector signals, the second number of detector elements being smaller than the first number of detector elements.