An apparatus and method are provided for implementing a camera function of a mobile communication terminal having a zooming function capable of enlarging or reducing an image. The apparatus and method include storing zooming levels of a camera such that the zooming levels are mapped to preset shutter speeds on a one-to-one basis, detecting a shutter speed corresponding to a requested zooming level in response to a user's request for zooming level control in a camera mode, and photographing an image according to the detected shutter speed upon the input of a shutter key for an image photographing operation of the camera. Therefore, it is possible to photograph an image at a constant brightness by varying a shutter speed according to the zooming level of a camera.