P: Flatfield correction behavior

[Alex Matiash]

Windows 10 64 with all updates, LrC 11.2

Long story short: Lr's FFC works not as described. Description tells that only first or last file in sequence is treated as the reference flat field frame, but actually every file is checked for uniformity, and if Lr decides that it is uniform enough to be treated as the reference - it is treated, and the next file treated as photo is corrected using this "new reference" file that actually is a real photo, just not-so-contrasty.

It leads to two issues:

- not all files are corrected

- if there is a file in the middle of the sequence that is not corrected, then files after (in the direction from real reference file) that file are corrupted.

Steps to reproduce:

- do as described in the guide: place a real reference file first or last in the sequence

- have one or more files with low contrast in the sequense

- perform FFC

ER: all files are processed using first or last file as reference.

AR: every file is checked for having low contrast enough to be treated as reference, and in case it is treated - all consequent files are processed using this file as reference, not the first\last.

Attached screenshots: with issue, and with hints where to look at. Take into account that LR processed files from the last to the first, as the reference is the last file in the sequence.

I can not attach photo file that is erroneously treated as reference because it exceeds allowed file size, but I can provide any files in some other ways if needed.

Just illustration

The same with hints

 

[Rikk Flohr: Photography]

The team has looked at your post and asks if it would be possible for you to provide us the set of files. You can share them from Creative Cloud/Dropbox or similar. 

[Alex Matiash]

Sure, here it is (I hope it was shared correctly):

https://www.dropbox.com/sh/5k8too3h7rzhpxm/AACwF_3ltS51zWsPgbhkvdv7a?dl=0

CF028267 - correctable

CF028284, CF028301 - treated as the reference

CF028302 - correctable

CF028303, CF028304 - treated as the reference

CF028334 - correctable

PhaseOne IQ180 Mamiya 210 inf @ 11 - reference

[Alex Matiash]

Well, somebody downloaded it so many times that it caused my Dropbox limits to be exceeded. So let's try Google Drive.

For all who do not REALLY need these samples - please do not download it!

https://drive.google.com/drive/folders/1Yh-XCKtGHGdFGwfwzyoBGl4tDYk2yaQr?usp=sharing

[Alex Matiash]

Hi! Is there any update with this issue?

[Rikk Flohr: Photography]

Greetings all, 

A new update for Adobe Photography Products has been released.  The December update contains an update for this issue. 

If you do not see the update in your Creative Cloud Application, you can refresh it by hitting [Ctrl/Cmd]+[Alt/Opt]+[ R ].

Note: It may take up to 24 hours for your update to be available in your Creative Cloud app.

Thank you for being so patient.

[rob_9037]

It's broken again in 14.1.1. It was working fine for the past couple years, but with 14.1.1 flat field correction is doing exactly what the OP describes. It's extremely annoying because I rely on this tool for one of my technical camera lenses.

Previously I would shoot the picture and then shoot the LCC frame. Flat field correction could handle individual pairs, or large groups of pairs. Now in 14.1.1 it can't do that, and it still doesn't work if I put the LCC frame before the image file.

[MMC12]

Good morning everyone,

In my case the December 2024 update completely solved the problem, thank you. I correct both the color cast and the vignetting with this plugin for a specific lens in my equipment.

In detail, before I had the same problem of the opener, and in some cases I had some raw images completely impossible to convert. Infact them remained RAW and never transform in .DNG with flat field applaied.

Furthermore, often it was necessary to work in small groups or the problem described initially occurred, especially if the photos were taken at night.

With this update I'm happy, the work has become really more simple and fast.

In my tests, the only case in which also with the last update the flat field correction failed (it was converted the flat field instead of the image that was supposed to be corrected), it was when the flat field wasn't the first image, but the last and the first was an image considred as flat field from the plugin, even if it wasn't like that.
This has never happened to me when keeping the flat field as the first image of the group (flat field image realized before the images to correct).

But in all other cases now it's ok for me and above all now it converts ALL images, also even the critical ones. Essential point this for me.

Regards

[rob_9037]

Good news that it worked for you. I find it very strange that in my case it was working fine, and now it isn't!

There's no sign of a December update either...

[rob_9037]

We're at the 14.2 update and it's still broken!

Adobe: this is so unprofessional. It was working and you broke it. Just fix this please.

[srdjanmitrovic]

I am having the following issues with the Flat-Field Correction tool in the 14.2 release of LrC (all Hasselblad 3FR files).

1) When selecting pairs (LCC and image), sometimes the LCC gets corrected instead of the image. In a series of 6 pairs, only one pair fails to correct properly. All others are corrected fine. All pairs are in the same order (image first, LCC second). This failure is intermittent.

2) The batch Flat Field Correction does not work. After selecting three pairs of images and LCC files, the batch correction starts from the last or the first image, regardless of whether the first or the last image is LCC. All photos get corrected using the previous image, except the first or the last, depending on how it started. This means that LCC files get corrected, and the non-LCC image gets corrected using the modified LCC file.

[rob_9037]

I've made some progress on this (version 14.2).

Flat field correction will work only if you (1) put the LCC image in front of the scene image, and (2) correct only one pair at a time.

It will fail if you put the LCC image after the scene image; it uses the scene image to correct the LCC!

If you try to batch process pairs of LCC/Scene, assuming the LCC is first in each pair, it will correct the first pair properly, and then it will mess up all the subsequent pairs.

So it's still broken, but at least it partially works and I can carry on doing flat field inside LR, which is what I need. However, it would really be nice if Adobe would kindly just fix this function properly. I know it's a niche function, but it's part of LR so it needs to work.

Thanks, Rob