C200: Canon C200 Sensor Issue

E

Ethan S.

New member
Hello,

Been doing some camera tests, and ran into a very strange problem.
When shooting into a bright highlight where the rest of the frame is underexposed or has black in the frame, I get a very weird flaring type of look on the sensor. It matches whatever source is creating the highlight and creates horizontal lines (looks like macro blocking or banding but in large strips) across the dark part of the images. When you canter the camera the horizontal lines thin out and then disappear after the camera is at about 45 degrees one way or the other. Really not sure what this could be. Tried multiple lenses, and got the same results.

Here is a video showing the issue:


The video was shot in RAW 23.976, transcoded into ProRes4444 in Canon CRD (the raw files show the issue as well).
The black sweater is being held to help show the issue, since the issue arises when there are darker elements in the frame.

Any thoughts?
 
Yes, that's normal. It exists in the C300mkii as well. It can get pretty nasty if you're not aware of it. It tends to strip out the green channel laterally across the sensor, leaving things with a magenta tint. Usually it will dissapate in the grade, but sometime is hangs in there.

I've come across it on the Red Dragon sensor as well.
 
My C300 MKII has this "issue" as well. I first saw it a couple of days after originally receiving the camera, when doing some initial testing and settings. I contacted the reseller immediately, they contacted Canon and after reviewing some sample footage Canon actually took the camera in, and replaced the CMOS??

However the new CMOS has the exact same issue.

The problem for me is, that I really like high contrast scenes and strong backlights. Any advice / experiences in how to avoid the issue or work around it in these situations?
 
I find it tends to happen when I'm trying to make everything in the shot work. Like trying to expose for an exterior that's 6.5 stops over and I end up letting my subject get down into the lower than 20IRE on the waveform. So it ends up happening a lot more in doc/verite work. For lit stuff where I just don't have the wattage to fight the exterior, I've just been letting them go!

TOTO_TEST_COLOR.00_13_37_00.Still058.jpg
 
This one had Canon change the CMOS on a brand new C300 MKII (Clog2, ISO 800, UHD 10bit)
CMOS 1.jpg

This one is from the new CMOS (Clog3, ISO 800, UHD 10bit) I have contacted Canon again, this time around their answer is that it is normal behaviour.
CMOS 2.jpg
 
I've seen this issue as well.

When filming scenes where the side of the sensor has large contrast, very light&dark areas, it seems to send a "streak" over the whole picture, seen in the shadows.

I don't recall seeing this with the C100, nor with my GH5.

This is MP4 only, we haven't got CFAST so can't try with raw.

https://vimeo.com/246960483/28eec44be5

Fixable in firmware? Well maybe, since I remember FS5 could fix some of it's sensor bugs afterwards.

I have tried with two C200 cameras, and the issue seems to go away on ISO 800, but visable in various ISO's over and under. So I don't know about "normal CMOS behavior" since it only shows up if the ISO is "wrong"..

I don't like that the ISO-function doubles as a on/off switch for these ugly light streaks if you change from ISO 800. =)

https://vimeo.com/246967169/a0ebc9585a
 
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