Lightroom Classic : Lens Corrections Profile Problem

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  • Updated 4 months ago
I am having a problem with lens correction function when images are shot in JPG.  I am using a Canon EOS 6D with a Canon EF 16-35L II.  When I click on Len correction it doesn't auto detection.  then when I go to manually select that lens profile is not available.  I only have a selection of 10-15 lens profiles.  When shot in CR2 it auto detects.  When I look at the list of available lens profiles there are 4-5x as many.  Why can't I manually select all lens profiles when shot in JPG?
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Michael Karchner

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Posted 5 months ago

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Johan Elzenga, Champion

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Most lens profiles are for raw only.
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Ruurd van Dijk

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When shooting jpeg most camera's apply lens-correction automatically already.
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Michael Karchner

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Makes sense.  Thank you!
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Justin McMurtry

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OK, but what if the camera has no idea what kind of lens is attached to it?

At the moment, I'm processing some photos that I took about a year ago, in JPG mode, with my then-new Fujifilm X-T100 body and a Samyang F2.0/12mm X-mount wide-angle lens. The lens is manual-control only and does not communicate with the camera; basically the camera thinks you're shooting without a lens at all. At the time, I was very new to the camera and hadn't gotten everything figured out yet; that's why these were JPG shots rather than Raw. Also, the X-T100 has a menu item where you can tell it the focal length of whatever "manual" lens you're shooting with. I don't know whether the camera uses that only for putting the value into the EXIF data, or if it goes beyond that in a way that influences its image processing somehow. At any rate, again, I hadn't gotten that figured out yet at the time, so the menu item was set to 50mm (which I think is the default value), rather than 12mm.

So, fast forward a year, and I'm sitting here with Lightroom Classic 9.2 and going thru these images. Some, I took with Fuji "smart" lenses, so I assume the JPGs were normalized in-camera. But with a "manual" lens, again, I don't see how the camera could've done any kind of distortion correction to the image as captured, knowing nothing about the lens.

The many, many shots I've taken in Raw format since then with the Samyang F2/12 are all fine; there is a Lens Profile specifically for that lens available in Lightroom Classic, and I apply it all the time. BUUUUTTTT.... I can only do that to Raw captures. If I try to do the same to one of these older JPG captures, the option simply isn't available. I've even tried applying the profile to a Raw, then copying only the Lens Profile component of the Develop settings from that Raw, then pasting those settings onto a JPG made with the same lens. Unfortunately, this doesn't work; if I then view the target JPG in the Develop module and look under Lens Corrections, there's a little error message that says, "(!) Unable to load lens profile."

Is there not some way to manually override or "force" a given Lens Profile to be applied to a non-Raw image? If the profile is basically just a tailored mathematical transform, I don't see why it couldn't be applied to any arbitrary raster image.
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Justin McMurtry

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Incidentally, I tried converting one of these JPG images to DNG from within Lightroom Classic, to see if the Lens Profile option that I want to apply would become available. It did not; LRC treats the DNG version of the image just the same as it did the JPG original.
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Johan Elzenga, Champion

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That was to be expected. You can convert a JPEG to DNG, but that does not make it a raw file and so the profile will still not be available. DNG can also hold RGB data.
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Justin McMurtry

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I tried it in order to test whether whatever code in LRC arbitrarily excludes the image from being accessible to the desired Lens Profile based its logic on the superficial fact that the file is in JPG format. Evidently, it isn't.

That doesn't change the fact that the exclusion is completely arbitrary. Correct me if I'm wrong, but a Lens Profile is simply a set of parameterized mathematical transforms that can be applied to an image, that will have the effect of reversing whatever geometric and chromatic distortion that a given lens has been found experimentally to cause. There's no reason that such a mathematical transform couldn't be applied to *any* grid of colored pixels, regardless of the data format in which they are encoded, and regardless of whether any kind of data compression has previously been employed. It's as if you were saying, "Oh no, you can't apply a __________ filter to a JPG. That only works on Raw files." The blank could be filled in with "Gaussian Blur", "perspective correction", "positive or negative vignette", and practically any other way that an ordinary photographic image can be digitally manipulated.
(Edited)
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John R. Ellis, Champion

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Adobe's rationale for not applying lens profiles to JPEGs is that there is no industry standard that says whether lens correction has already been applied by the camera to the JPEG. However, you can easily edit a lens profile to support JPEGs:
https://feedback.photoshop.com/photoshop_family/topics/acr-lightroom-when-will-my-lens-profile-be-av...