A zoom lens including subsequently from an object side of the zoom lens to an image side of the zoom lens: a first lens group with a positive focal length; a second lens group with a negative focal length, an aperture arranged on an object side of a third lens group; the third lens group with a positive focal length, a forth lens group with a positive focal length. A method for driving a semiconductor memory device in accordance with the present invention includes sensing a current temperature in response to a control signal and entering a power save mode for a predetermined time starting from an activation of the control signal, wherein the power save mode has substantially no power consumption. Horizontal linear segments are joined end to end to define a waist of polygonal cross-section. The subject technology retrieves information associated with the selected person of interest. In a light-emitting device having such a structure, an image is displayed by combining emissions from the plurality of light-emitting elements. The apparatus includes a sound processor adapted to process signals from the first microphone to produce a processed sound signal, a receiver adapted to convert the processed sound signal into an audible signal to the wearer of the hearing assistance device, and a voice detector to detect the voice of the wearer.