A portable electronic device has a device housing, and an electronic camera module in the device housing. The module has a focusing lens to focus light from a scene, an imaging sensor to receive the focused light, and an electro-optic variable aperture to allow different amounts of the light from the scene to reach the imaging sensor. The electro-optic variable aperture may include a first aperture stack placed on a transparent substrate and a second aperture stack placed on the first aperture stack. The first aperture stack defines a first aperture and the second aperture stack defines a second aperture that is larger than the first aperture. Each aperture stack includes a transparent conductive oxide layer that is common with the adjacent aperture stack. Alternatively the electro-optic variable aperture may include an aperture stack that has two transparent conductive oxide layer layers, where one layer is in the form of concentric annuli.