Lightroom Classic: Flat field correction not seeing LCC as first file

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  • Updated 6 days ago
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Not often but many times I get an error message saying "Flat field correction must be first next to images" (something like that). Has anyone else experience this error? Is there something I can do to correct this.

I am using a Phaseone IQ3 100 and a LCC on a technical camera . I am able to Apply LCC in CaptureOne. I prefer to use Lightroom so all suggestions welcome.
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Bob Graham Jr.

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Posted 2 weeks ago

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Johan Elzenga, Champion

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Sounds as if the error is simple. Your must have the FFC image selected as the first image, and it seems you have not done that.
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Bob Graham Jr.

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I have selected just the file and the LCC. Both are next to each other.

I have done this many times and it works... except when it does not.

Thanks for your comments.
(Edited)
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Simon Chen, Principal Computer Scientist

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See https://helpx.adobe.com/lightroom-classic/help/flat-field-correction.html

The first or the last of the photo selection must be a flat-field calibration frame, otherwise Lr would not know the sequencing of your shoots.
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Simon Chen, Principal Computer Scientist

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If you did that and it still complains, then it is likely that Lr failed to detect your calibration frame as such. There is some threshold where Lr consider a blank frame as really looks like a calibration frame. Here is one workaround: 

  1. Open Lightroom.
  2. Invoke Lightroom > Preferences... menu command
  3. When the Preferences dialog appears, select the Presets tab.
  4. Click on the button labeled “Show All Other Lightroom Presets...”
  5. Lightroom will reveal the root preset folder in the Finder/Explorer.
  6. Now download the config.lua file and copy it into the Lightroom preset folder that Finder/Explorer selected at step 5. 
  7. Relaunch Lr. 
  8. Invoke Lighroom>Help>System Info... menu command. You should see a section that shows the following

Config.lua flags: 

FlatFieldOption.ReferenceDetectErrorThresholdMultiplier = 6


The Lr default for such FlatFieldOption.ReferenceDetectErrorThresholdMultiplier is 4. You can try to edit this config.lua file in a text editor to increase/decrease the value of this multiplier. Increasing this threshold to high will risk Lr detecting every photo as a calibration frame; whereas decreasing the threshold will tighten the criteria.


(Edited)