there is a free application called hdri shop. You can download it here: https://athens.ict.usc.edu/HDRShop/

there is also another way you can use hdri images. there is a plugin for hdri shop that will create a mel script that will create lights from the hdri image. You can find the tutorial here: https://myhome.hanafos.com/%7Eutan0810/tutorior.html

and the mel script here: https://www.ict.usc.edu/~jcohen/light...gen_plugin.exe

that is just for faking it. It is good for maya software rendering. But for mental ray you can use the IBL node to use the hdri file.

Hope this helps mate.