Not Finding Lens in Lens Profile

[Jeff A. Goulden]

For some reason I am no longer finding my lens under "Lens Correction/Enable Profile Corrections".  It lists a handful of lenses, non of which is the one that took the picture.  However, the metadata in the Library Module recognizes and displays the correct lens that I used.  I looked at some older pictures and they had the correct profile information. 

Actually, I'm not even sure what the Enable Profile Corrections actually does but it doesn't seem right to have the wrong lens listed.  My camera is a Nikon D750 and the lens is a Nikon 24-120mm zoom.

I am having some problems with the camera and had to restore it to factory defaults.  I'm wondering if that has something to do with the problem.

[Jeff A. Goulden]

Never mind!!  I just realized that the file has to be a RAW file in order to use the "Lens Correction/Enable Profile Corrections feature.  When I restored the camera to factory defaults it started shooting JPG files.  I still don't know exactly what this feature is for though.  Can anyone explain in simple terms.  Thanks.

[Ian Lyons · Accepted solution]

The profiles correct  issues inherent in most lenses. For example, barrel  and pincushion distortion, vignetting at corners, and chromatic aberrations.

If you want to learn more about these issues, then best you do a search using Google as there are plenty of articles and videos that explain / demonstrate each in much more detail than I have above.

[Jeff A. Goulden]

Thanks!!  That was helpful.

[richardplondon · Accepted solution]

Somebody has used this lens and camera (profiles are specific to a combination of those two) to take a lot of test shots of known checkerboard pattern targets. Those shots are then analysed by software to see how the actual test shots DIFFER from how a perfectly performing lens would have portrayed those same known targets.

If needed, for example with an unusual lens or a mount adaptor say, the end user can generate their own custom profile - though this is not quick or easy to do. 

The profile provides a set of corrections that can be applied to photos taken with that particular lens/camera, as gleaned from all those test shots, which will largely reverse out whatever optical 'imperfections' this lens and sensor combination may exhibit.

Sometimes a lens is made cheaper / simpler / lighter / smaller than it otherwise would have been, by deliberately designing-in for some correction to happen in software, rather than by eliminating it in the lens by adding corrective glass. 

Lens profiles do not address chromatic aberration though - which LrC deals with differently.

Many cameras have got lens correction information built-into their firmware, covering their fixed lens / those interchangeable lenses that the camera body is able to 'recognise'. Typically that correction is already incorporated by the camera onto the JPGs that it saves, in which case no further lens correction needs to happen. For many camera manufacturers an agreement has been reached with Adobe that such correction will also be extracted from Raw files and applied without the option. In that case no selection of a named Adobe lens profile is then necessary, or possible. So sometimes no lens profile is listed even for Raw - because that will always have already been applied automatically.

[Jeff A. Goulden]

Thanks for the helpful information.  Much appreciated.