title: The problem of optical tolerances for systems with absorption.
abstract: The setting of aberration tolerances is considered for systems in which the emergent wave front has a nonuniform amplitude across a full circular aperture. Tolerances can be derived from the transfer function for a specified spatial frequency; no simple equivalent of Maréchal's tolerances can be derived to suit all cases well, although limits can be given.
authors.forename: W H
authors.initials: WH
authors.lastname: Steel