Why do you need HDRI when you can just set the light?

Question

3D

I am learning from tutorials on YouTube, but I don’t understand why HDRI is needed, if you can just set the light yourself?
And then, if there is HDRI, why then set the light manually?)

Answer 1

With HDRI, background lighting is set, mainly for exterior scenes. Because manually it is very difficult to convey all the details of the lighting that comes from the sky. There are complex clouds, scattering, spectrum changes at sunset, and so on. It is enough just to take a series of 360 photos with different exposures and special software will turn this into an HDRI card. Well, or just download the finished one.
For interior scenes, HDRI is used only in the subject, when it is necessary to illuminate some object, as if it were in this interior. This is especially useful when making a video where some kind of CG object is inserted into a real video sequence. You just shoot the HDRI from the set and don't worry about manually adjusting the lighting of the subject, it will be very natural and appropriate for the video.