Corona is a highly capable photorealistic renderer available for 3ds Max and soon for Cinema 4D and Maya (which are currently in public alpha stages). It also has a standalone CLI application. If you’re a Blender user, this means that you can use the renderer with Blender thanks to a 3rd party exporter.
The Blender to Corona exporter allows you to use the standalone with Blender scenes. The interesting part is that the Standalone doesn’t require you to have a license to use it — It’s free to use. If you have a 3ds license for the renderer, you can use the installer to get the standalone. If not, you can follow this link.
The Render Legion team posts a quick-start guide to get you set up with the unbiased renderer and Blender. The video shows you how to get the Exporter and Corona Standalone up and running.