For some forum members need to know what Chromatic Aberrations are.
The issue is with the LENS. Not to worry, almost all lenses have minor to major issues with Chromatic Aberration.
The image is RGB or red, green and blue layers or channels.
All the x,y pixel layers must align themselves properly for no aberration effect.
So pixel at position x=0 and y=0 (image upper left corner) all the RGB pixel layers must be direct over top
0,1,2,3,5,6 -> Red layer
0,1,2,3,5,6 -> Green layer
0,1,2,3,5,6 -> Blue layer
aberration occurs when the RED layer or channel is offset by 1 or 2 pixels pushing the 0 pixel offset and is seen in the image.
X,0,1,2,3,5,6 -> Red layer
0,1,2,3,5,6 -> Green layer
0,1,2,3,5,6 -> Blue layer
Photoshop and other graphic editors have a modules that will help to visually reset the red pixel layer back into place.
Photoshop's module is called Adobe Camera Raw Converter (ACRc). Converts Canon Raw .CR2 images to .tiff
ACRc tool is shown below:
- Chromatic Aberration
- acrca.jpg (70.92 KiB) Viewed 25906 times
- Chromatic Aberration Gone
- acrcagone.jpg (69.14 KiB) Viewed 25906 times
JPEGs: Photoshop also corrects Chromatic Aberration (CA) in jpg images by using Adobe Bridge. Open Bridge and browse to the folder where your jpeg images are located. When we use our Sigma 8mm fisheye lens we shoot 4 image at 90° intervals. In Bridge (not shown) select the 4 image set and Photoshop will open ALL 4 using ACRc (instead of just one .jpg). In the Upper left corner click "SELECT ALL" for adjust 1 image and the changes are made in the remaining 3 images. SAVE AS (lower left ACRc corner) out to filename1 .jpg or .tiff. Now you have original jpg and 4 new corrected files with new names.
White balance may also be adjusted by selecting the eyedropper and clicking on a white object in the image. This tells the image "What is KNOWN white" and corrects the remaining other image colors accordingly. Miss colored light is caused by the area lighting might CFL flourescent, incandescent, LCD or newest light source LED OR normal outside daylight. OR a mix of different primary light sources.
- White Balance
- acrwhite.jpg (93.25 KiB) Viewed 25906 times
But you probably already knew these techniques. Its worth the time to refresh the topic.