I've been researching a strange Canon bug and I thought this would be the place most capable of understanding/investigating the issue.

In searching the internet and talking to some people with various Canon cameras, it seems like many of them have an issue where in both video and JPEG stills, a bright blue light will become purple/pink. The intensity of it must be very high in order to cause this to happen, but I was talking to someone who said it ruined a paid gig they shot on the C300MkII at a company who's logo was blue and had lots of digital signage all over their facility which turned purple in the footage.

I've found sporadic reports of it on the 60D and the 5D Mk IV, but I don't have any Canon cameras to test this further. In looking at sample photos people have posted, I suspect that the issue is in software, where Canon is perhaps not truncating a pixel with an extremely high blue value but overwriting the adjacent red value for the next pixel instead. In some sample photos, I've gone to the blue channel, and selected every pixel which was pure white, then gone to the red channel and adjusted brightness down and you can get very close to what the original image should have been. Since this issue is not present in RAW, the issue seems to be beyond the sensor and in the software side of the camera possibly in Canon's JPEG processing since they Motion JPEG encoding for video and it is present there as well as JPEG stills.

Has anyone ever heard of / seen this issue before? It seemed interesting enough to research some more. Anyone with a Canon camera try shooting a bright blue LED light in either JPEG stills or video and report back if it does it. I wonder if every Canon camera will exhibit this behavior.

References:

https://community.usa.canon.com/t5/EOS/Blue-LED-Lighting-showing-up-as-purple/td-p/51017 https://www.dpreview.com/forums/post/58433003