TOPIC:

I am in the process of reorganizing my LUT collection. I notice that there are two folders inside Library/Application Support/ProApps/…

Camera LUTs and Custom LUTs

What is the difference? I have LUTs in both folders that must have been put there as I was playing around with things, but I don't know exactly what made some go in one folder vs the other.

Thoughts?

Camera LUTs appear in the Camera LUTs popup on the Settings inspector. They can be added directly to clips in the Browser or the project and get processed first. Custom LUTs appear in the Custom LUTs effect, can be added to clips in the timeline, and get processed in whatever order the effects are organized in the Video inspector.

In general, to add to Tom's on target explanation, a camera LUT is created to help get started with a specific type of clip from a specific model of camera. Mostly LOG and other specialized shooting formats. A "looks" LUT ("Custom" in this case) are created to be applied at the end of an edit, to closely match the look of a specific film, or whatever. Look LUTs are frowned upon by some professional colorists as the lazy amateur's way out of learning to grade. I personally have experimented with Look LUTs a lot, and I've never found them to do anything of value. But, other editors love them. Personal taste. Camera LUTs on the other hand, are applied either upon import of in a specialty app just before import into an NLE, and are technically a huge help at times. So, there you have it, information you didn't ask for...

So which would the FilmicPro Luts go in, Camera or Custom?

I would say Camera since they are disgned for the camera correct?
FilmicPro itself say save them in the Custom Folder.

Just be aware that FCP will become nearly unusable the more custom LUTs ( >100 ) you add - this is a known bug by Apple which will hopefully be fixed in the future.