An exemplary objective holder engages with a PCB substrate having an image sensor and several passive components arranged thereon. The passive components surround the image sensor. The objective includes a lens barrel extending from a side of a base, and a plurality of walls extending from an opposite side of the base. The walls enclose a chamber thereamong for receiving the image sensor and define notches therein for receiving the passive components therein. A transparent cover is received in the objective holder between the lens barrel and the chamber. An adhesive is used to connect the objective holder to the PCB substrate. The PCB substrate is rested on the walls. At least one of the notches communicates the chamber to an exterior for outgassing and is sealed by a mass of sealing material after a heating process of the adhesive.