Directional light lux and exposure

Recently whilst going through some youtube lighting tutorials I came across some advice I’ve never seen before and cant seem to find anything to confirm or deny the advice. So just wondering if anyone follows this train of thought.

The advice is set the directional lights intensity to 1 lux and then use exposure settings to achieve the level of brightness that you want, rather than what I was doing before which was to clamp exposure min/max to 1 and then increase the directional light lux.

To be fair it does seem to be reasonable advice and works quote nicely. Does anyone do this as best practice?

If you want a realistic result, ideally you would use real world values for light intensity and set the exposure according to which parts of your scene you want to be fully exposed.

From an artistic standpoint it might(?) be useful to reduce the intensity of the directional light to in order to expose more of the scene.

Would you use the extended default luminence in the project settings aswell if using real world lux values?

You can tell I’m not an artist :wink:

Thanks for the advice :slight_smile:

I probably should have mentioned their reasoning for the value of 1 on the directional light. Supposedly high lux values break PBR, is that a load of nonsense?

Yes, enabling extended default luminance is pretty much a requirement. In my opinion Epic should make this the default.

You’d have to elaborate on what is meant by “breaks PBR”. This is the first I’ve heard of this, and I can’t think of any reason why that would be the case. I am not a graphics engineer though so even with more detail about the statement I’m not sure I could give you a definitive answer.