A system having a sensor and variable focus lens for iris image standoff acquisition. The sensor may capture a sequence of images at a high frame rate of a person for getting an eye or an iris in a window within the images. Even if the eye moves around in the image, the window may stay on the eye. During this capture, the focus of the lens may be changed, with a best focus situated somewhere in between the end focus positions of the lens. The sensor may be an infrared (IR) sensor and an IR illuminator or flash may provide light for the capture of images. An intensity variance indicator may be incorporated to select an in-focus image of the sequence. Processing of the images may be subsequent to the capture of images, thus not hindering the frame rate of the system.