I believe the lens information is from the raw’s themselves—something the camera puts there, or internal CR-engine coding in the for lens profiles. Not from .lcp files, at least.
This is what happens for mirrorless cameras, mostly, now, the lens profile is built-in and always on without any .lcp file to supply the information, which also provides a source of endless confustion, at least until now, when both LR and ACR have an info balloon in the lens-corrections are that says a profile is built-in.
You are right! Should have said that I'm testing with ARWs from a Sony A7. Never noticed that info balloon in LR but it's there and says that the raw file has a built-in profile for chromatic aberration (which explains the calibration matrix, which is a pure colour shift).
I checked all the ARW metadata with exiv2 but nothing like this showed up - guess it must be hidden somewhere in the MakerNotes and not decoded yet (at least not by exiv2 - clearly by Adobe).
Thanks for this, very helpful. 2 follow-up questions:
- Is there any (preferably open-source) program/library that can extract the built-in profile from the raw (specifically ARW 2.3)?
- Does that have implications to using LR's lens-correction, i.e., should I not use LR's CA-correction anymore if it uses the built-in already (or does it not make a difference)?
I can’t answer about a library to read lens information from the raw file.
LR-selectable profiles correct geometric distortion and vignetting. CA is handled by a checkbox and not part of the selectable profile, anymore. So if the built-in profile only corrects CA then using another profile to correct geometric distortion or vignetting is ok as long as it’s for the lens you’re using. If the built-in profile is correcting vignetting and/or distortion and then you select a profile that also corrects those things they you’ll have double-correction and things won’t be right, i.e. the corners will be lighter than they should be and the distortion will be the other way, barrel for pincushion and vice versa.
dcpTool can extract the camera profile (.dcp file) from a DNG
The request was how to extract the lens profile from the raw file, the ARW, not the DNG.