A liquid lens includes a segmented electrode that allows the simultaneous application of different potentials across the lens's meniscus to obtain a predetermined aberration correction condition and to adjust focal length as necessary to conform to the topography of the object being scanned. The lens also includes a gas plenum interfacing with one of the liquids of the lens to allow for volume changes in the lens cell due to temperature variations. This combination of features produces a liquid-lens cell capable of maintaining substantially constant transverse magnification and diffraction-limited image quality over a useful range of focal length. As such, the lens is particularly suitable for incorporation in an array of micro-objectives used in a scanning microscope.