In answer to the questions raised by Ferrari and Garbusi [Opt. Lett. 29, 1257 (2004)] we indicate that, even if the intensities of the object and reference waves can be measured, the phase-shifting procedure is still necessary for correct reconstruction of the object wave field. We also show that the statistical approximation used in our previous Letter [Opt. Lett. 28, 1808 (2003)], <\sin phi(o)(x, y)\> 2/pi, where phi(o)(x, y) is the phase of a diffraction field and <> means average over the whole interferogram frame, is reasonable for most objects, including both smooth and diffusing surfaces, and that the method we proposed for phase-shift extraction is correct. (C) 2004 Optical Society of America.