The purpose of this study is two-fold: first, to investigate the spatial quantization errors on the image plane; second, to discuss a speed/accuracy trade-off between axial and lateral stereo (conventional stereopsis.) Triangulation errors in 3-D point position estimation are analyzed with analytical approximations and verified with extensive numerical simulations. A performance comparison to conventional stereopsis reveals a trade-off between accuracy and speed for axial stereo, which could be tailored to fit one's performance requirements. We pay attention to the anisotropy of rectangular image tessellation, since log-polar sensors are still uncommon. [Tis90] And we do not assume on any particular log-polar mapping techniques such as in [Bar90], [Jai87], [Tis91] and others.