E-foto is free software, distributed under the terms of the GNU Public License,

This is an academic initiative to develop free software for Digital Photogrammetry. The E-Foto project has been in development at the Photogrammetry Lab of the Rio de Janeiro State University’s School of Engineering since 2004.
The idea behind the E-Foto project was to offer a simple set of software (a free Digital Photogrammetric Workstation) that could help students understand the principles behind Photogrammetry, thus bypassing eventual costs that would have barred many from learning about Photogrammetry. This objective was reached through the development of free and user-friendly photogrammetric software.
This project is multidisciplinary. It involves several fields of knowledge, including Mathematical Modeling, Geodesy, Photogrammetry, and Software Engineering.
The project is based on two main principles (pillars): freedom and self-teaching. The final idea is to lead the students to fully understand the principles behind Photogrammetry by reading the e-book, using the software, taking a look at its source code, and even modifying it or developing new modules for it.