Ben Benton shares a great tutorial on creating HDR images from Cinema 4D scenes which is a great way to amass a library of useful HDRs quickly just over the course of normal day to day production.
Quick and dirty tutorial on how to bake your scenes out to work as HDRI’s for GI or just a reflection map
HDR’s for lighting information or even reflections usually need to be distorted into a lat-long, or an image that is in curvilinear perspective.
Although some applications and third party renderers will allow for this type of rendering directly from the engine or even through lens shaders, Ben creates this effect by using a reflective, non-shadowcasting sphere in Cinema, and baking the texture out with the Bake Texture tag which is a simple way to get the same result.