A variable focal length lens consists of many micromirrors with degrees of freedom rotation and/or degrees of freedom translation and actuating components. As operating methods for the lens, the actuating components control the positions of micromirrors electrostatically and/or electromagnetically. The optical efficiency of the variable focal length lens is increased by locating a mechanical structure upholding micromirrors and the actuating components under micromirrors. The lens can correct aberration by controlling each micromirror independently. The lens can also be of a desired arbitrary shape and/or size. The micromirrors are arranged in a flat plane or in a curved plane with a predetermined curvature. The electrodes determining the position of the micromirrors can be made of material with high electrical conductivity, preferably metal. The surface material of the micromirror is made of a material with high reflectivity such as aluminum, silver, and gold, which are coated with multi-layer dielectric material or antioxidant.