3DF Zephyr is the complete photogrammetry software solution by 3Dflow SRL.
It is available in four flavours: Free, Lite, Pro and Aerial - the full feature list is available over 3dflow.net.
Although all the editions share the same underlying proprieatary and state of the art reconstruction technology, the available features and tool are very different.
3DF Zephyr Free
3DF Zephyr Free is a completetly free edition that in addition to its viewer capabilities (great to share Zephyr project files with customers and friends) can compute up to 50 photos. Although it has limited computation capabilities and a reduced set of tools, it's a great package to start learning photogrammetry.
3DF Zephyr Lite
3DF Zephyr Lite is the entry level edition, excellent for hobbysts and small business users. It allows up to 500 images and has additional tools compared to the free edition: it lacks however the laser scanning integration and control points, among other features available for 3DF Zephyr Pro and Aerial. It is also available as Steam Edition
3DF Zephyr Pro
3DF Zephyr Pro has no computation limitations but lacks some post processing tools that are mostly used by surveyors. It includes control points and laser scan integration, making it the best solution for pure 3D modelers professionals.
3DF Zephyr Aerial
3DF Zephyr Aerial has no computation limitations and includes all the available tools for 3DF Zephyr.