The balance between internal and external lighting has always been something i’ve tried to find a solution/workflow for. I definitely try and go down the physically accurate route setting up the internal lights to realistic (or close to realistic) values. But before i worry about that i setup my camera to settings i would expect to use as a starting point in a real world scenario. Those of you that have heard of the sunny16 rule will know that there are fairly specific guides to a range of lighting scenarios. (See attached a chart that i knocked up for the studio).
These are obviously guides, not law, but they’re a good starting point! I start off with these settings, so for an internal something like F2.8, shutter speed 1/125 and ISO 100. Since the level of light you get from your HDRI can differ entirely depending on who has shot it and what number of stops have been used to capture it, therefore there is never a truly accurate value to set it at as per the values of the vray lights. Therefore i boost the render output value of the HDRI (leaving the vray dome light on 1.0) until i a level of light in the scene i’m happy with. I’ll then turn on my internal lights individually or in groups depending on how i want to go about lighting the room. 9 times out of 10 they’ll only need minor tweaks if any.
Hope that helps, works for me anyway!
