The present invention relates to optical unit comprising, seen in the direction from the object side to the imaging surface, a first substrate, a first lens, a second lens and a second substrate, characterized in that the distance [(vertex first lens) and (vertex second lens)] is 250-650 pm. Such an optical unit is used, inter alia, in image processing units, such as cameras. It is an object of the present invention to provide an optical unit in which the desired dimensional precision of the lens system can be accomplished without this leading to an undesirable increase of the optical unit's dimensions.