We present the concept of using a photon sieve as an inexpensive null-corrector. A photon sieve is a diffractive element consisting of a large number of holes precisely positioned according to an underlying Fresnel Zone Plate geometry. Using diffraction theory we can enlarge the holes significantly beyond the width of a Fresnel zone such that more light is transmitted and greater efficiency is achieved. Added to this, modification of the equations used to generate the hole locations can also permit the construction of any desired wavefront instead of a simple infinite-conjugate ratio focusing optic. This makes it an ideal optic for testing larger components in a null-corrector configuration. In this talk we will present theoretical and experimental results from tests of this idea. These include the fabrication of a 0.1m diameter intensity photon sieve null-corrector specifically for testing a parabolic primary.© (2006) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.