The imaging apparatus comprises a light-tight enclosure in which are enclosed: a detector adapted to detect a light signal emitted from a sample, a reflecting device comprising first and second reflecting portions reflecting toward first and second portions of the detector a signal emitted from first and second portions of the sample, the second reflecting portion reflecting toward a third portion of the detector a signal emitted from a the third portion of the sample and previously reflected by the first reflecting portion, a fourth portion of the detector directly detecting a signal emitted from a fourth portion of the sample.