Color casts from lenses are quite a common occurrence on technical cameras. It can occur not only with wide-angle lenses but it can befall other focal lengths, particularly if extreme shift movements have been applied.
This troublesome effect is caused by the outer image-forming incident rays from the lens striking the surface of the sensor at oblique angles. At worst, it’s highly visible regardless of the scene, however, in its most nuanced form, it can only be detected in images with neutral gray or white backgrounds, where typically a green cast can be seen in one corner of the image and a magenta cast in the opposite corner.
Those are not just technical cameras that exhibit color casts, the effect is common with rangefinder cameras and other mirrorless models including cameras with non-interchangeable lenses where the rear lens element is positioned close to the sensor, particularly in wide-angle lenses.
Reflex cameras, however, rarely exhibit color casts, especially when using fixed (i.e., not zoom or tilt and shift) lenses between 60mm and 120mm focal lengths.
Illumination falloff in lenses where the corners of the frame darken is even more common across all formats and lens types. Both uneven illumination and lens casts can be corrected in Capture One on supported RAW files using the Lens Cast Calibration (LCC) correction tool. Additionally, the tool can be used to create a dust map to automatically remove sensor dust from images.
Capturing a characterization image
Correct an image with the LCC tool
Creating an LCC reference image
Apply LCC correction adjustments
Permanently update LCC correction data and profile
Saving LCC correction data as a User Preset
Thank you for this very interesting information. I think I might be having that issue with Sony A7R4 and 85mm GM lens, where for correctly exposed and WB-ed portrait a neutral background always has hue(s) in it.
Where can I buy a LCC plate to use?
Thanks for your comment.
Please check this article https://support.captureone.com/hc/en-us/articles/360002583718
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