Originally posted by dadipentak Went to that wikipedia article to see what this was about, Had to lie down until my head stopped spinning, Decided further investigation of flat-field correction was unlikely to result in significant improvement in photos of my dog. Sighed with relief and went back to screwing up simple stuff.
This technique is helpful if you are shooting raw and use raw converters that deliver no lens profile for your lens.
By example I use the DA*11-18 down to 15mm in FF mode on my K-1 - it clearly shows visible vignetting. 15mm is the widest you can go without lens hood on FF. Shorter FL shows the image circle. No lens profile in Capture One, RawTherapee or Affinity Photo. These are the raw converters I use. The vignetting standard tools suffer IMO.
But using prepared LCC / Flat Field Correction you get really rid of any vignetting - if possible. Another example: you use a 100mm Filtersystem and want to get rid of one sided shading. No problem if you first shoot the scenery trough opal glass and create a special LCC profile from it. Much better and easier than applying a digital GND in post.
This technique works for every lens - but you have to shoot raw. It costs some effort. If you don't like this, it's surely nothing for you.
Illustration:
Vignette of DA*11-18 @ 16 f/8 in K-1 FF mode
LCC profiled in C1Pro
C1Pro LCC corrected image - first single frame of a PSR capture
This image is a PSR image. At the moment I have to decide to develop as PSR with vignetting included or apply the LCC profile. It would be nice if it would be possible to develop such images as LCC / Flat Field corrected PS images in Raw Therapee.