Using Camera Profiles from a different model

And the OP is not currently involved, so we are not able to clarify what profiles are involved. if it were the DCP ones, and the OP had say LR Classic CC v 8.1 (perhaps even as early as 7.3) then modifying DCP profiles would be moot, as both cameras the OP listed have them in LR.

I, for one, misread what was being stated and asked, got off on the wrong track, may still be on the wrong track.And compounded that by answering the wrong question with the wrong answer.

We need feedback from the OP

Todd's answer is the correct one if the profile is a .dcp profile. I was just going to post the exact procedure he mentions after reading the original post but he was faster (and more thorough). I would guess that the original poster bought one of the old-fashioned creative presets such as those for film simulation that several companies offered or for other creative effects. Those presets used to come with camera-specific .dcp files. If that is the case, the OP would hardly be bothered by small deltaE values but is just attempting to achieve a certain look. Of course we don't know whether this is one of those profiles but probably not a bad guess.

Loftus  wrote I have a Lightroom camera profile that I used to use with my Sony A7R II, however I can't seem to use it on any photos from an A7R III. Is there anyway to modify the profile or otherwise use it on a different (albeit similar) model of camera?

Ok, I am completely confused. I suspect I first read this wrong. And I should have asked a few questions.

1. What version of Lightroom  are you running? If it v6.11, update to 6.14 to get the A7R III support. If you are running the subscription, then both cameras are supported. Cameras supported by Camera Raw

2. Are you talking about the Camera Matching profiles? If you are running old LR then thats down in the Calibration panel (although not called that). if new LR Classic CC 7.23 or newer its up in the Basic Panel, within Profile.

So, please accomplish the following

In LR, click on Help, click on System Information, click on Copy. Paste into response, along with your clarification.

Loftus  wrote I have a Lightroom camera profile that I used to use with my Sony A7R II, however I can't seem to use it on any photos from an A7R III. Is there anyway to modify the profile or otherwise use it on a different (albeit similar) model of camera?

Perhaps an opps moment.

By Camera Profile, are you refering to a Camera Matching Profile (Basic tab/Profile) a third party Profile preset (same general location) or a Develop Preset?

IF, the cameras used the same sensor, and the same processor, if this was just a matter of a new model out using same tech, you could, that would involve a Metadata hack of the file.

As they are different sensors, this would not work, it would if actually pulled off provide very crappy results.

You sometime see this in camera specific forums when a new model comes out that has the same sensor and processor as a camera already supported in ACR. But not for a completly new rig with a different sensor, and/or a different processor (will a different processor always accompanies a differnet sensor)

Short answer is no. You can't and you shouldn’t.

Loftus  wrote I have a Lightroom camera profile that I used to use with my Sony A7R II, however I can't seem to use it on any photos from an A7R III. Is there anyway to modify the profile or otherwise use it on a different (albeit similar) model of camera?

Apart from the question how useful that would be (these cameras have different sensors), I don't think there is if you are talking about a .DCP profile. These camera profiles are not plain text.

If it is a 'creative profile' in XMP format however, then you can change it so it can be applied to any camera. Open the profile with a text editor and look for  crs:CameraModelRestriction="whatever"  Set this to  crs:CameraModelRestriction=""