Examples of the disclosure relate to apparatus, methods and computer programs for enabling sub-pixel information to be determined in captured images. The apparatus can comprise means for activating at least one filter wherein the at least one filter is positioned in front of at least one image sensor. The at least one filter is configured to at least partially filter light such that the at least one filter has a spatial variation of transparency on an analogue scale across an area covered by the at least one filter. The apparatus also comprises means for detecting an image captured by the at least one image sensor; and using information relating to the spatial variation of transparency of the at least one filter to determine sub-pixel information in the captured image.