Abstract: A kit (10) includes a light source (12) and an optical system (14) equipped with a lens assembly (25) defining a magnification optical axis (X-X). A frame (16) is crossable by the light generated by the light source (12). The frame (16) is configured for supporting a sample holder (H), a portable electronic apparatus (S) equipped with an image acquisition device (C), and the optical system (14), which are interposable between the sample holder (H) and the image acquisition device (C). The optical system (14) is configured for being movable in a guided manner on the frame (16), to allow aligning the optical axis (X-X) with the image acquisition device (C). A carrying body (18) is configured for receiving in abutment the frame (16) and housing the light source (12) directing light towards the optical system (14) through the frame (16).