An applicator suitable for converting a white-light endoscope into an endoscope for combined white-light/fluorescence imaging is disclosed. The applicator facilitates attachment of an optical element, for example an optical filter, to a distal optical port of an endoscope. The applicator engages with alignment feature on the endoscope's distal end and releasably supports the optical element in an opening that is aligned with the optical port. The optical element is released in a proximal direction by pressing down on an actuator.
