With digital holography one can record and reconstruct real world three-dimensional (3D) objects [1,2]. The recorded interference pattern includes information about both amplitude and phase of a wavefront reflected from or transmitted through the object. However, some of the hologram capture setups pose a problem for the reliable reconstruction of quantitative phase information. This can be because the twin image or noise corrupts the reconstructed phase. In such cases it is usual that only amplitude is reconstructed and used as the basis for metrology. A focus criterion is often applied to this reconstructed amplitude to extract depth information from the sensed 3D scene [3,4]. In this paper we present an alternative technique based on applying conventional computer stereo vision algorithms to amplitude reconstructions. We show the effectiveness of our technique using digital holograms of both macroscopic and microscopic real-world 3D objects. We discuss sensitivity to the depth of field of reconstructions, and which hologram capture setups are, and which are not, suitable for the technique.