Does my C100 Mark II have a defective sensor?

[Philipp Sokolean]

I've gone through some footage I shot the other day and next to a sometimes extreme green cast I also noticed something even more unsettling. Some of the shots have a big fat green line going through the picture horizontally. I have attached 2 pics with the aformentioned issue. Does anyone know what causes this? Could it be that the sensor is defective?

[Darren Levine]

i occasionally notice some similar behavior in my mark 1, but only at higher iso in low light (as far as i can tell)

i haven't done any testing, but try a black balance.

[Philipp Sokolean]

I black balance after every lens switch but it's possible that I forgot... I never go higher than ISO3200 though.

[Gary Huff]

Originally Posted by Philipp Sokolean

I black balance after every lens switch

That's not when you black balance. You do it after significant temperature changes in the environment, after the camera has set dormant for a while, or if you've done a lot of ISO ramping up and down.

I've never seen a green line like this from any of my C100 series bodies (both Mark I and II).

[Alex Harper]

What lenses are you using and is the green line moving across the sensor? Judging from the pics provided it looks like an issue with backlit scenes. Could it be the that the lens front coating is degraded & not handling reflections well? I have never seen this on my two C100's, I only ABB once before every shoot.

[Jon Roemer]

Originally Posted by Philipp Sokolean

I've gone through some footage I shot the other day and next to a sometimes extreme green cast I also noticed something even more unsettling. Some of the shots have a big fat green line going through the picture horizontally. I have attached 2 pics with the aformentioned issue. Does anyone know what causes this? Could it be that the sensor is defective?

Do you have a filter on your lens? IOW, could it be a backlit scene which is reflecting internally on the filter?.... Some filters make ghost images of very bright highlights, they usually have a slight color cast to them.

[Philipp Sokolean]

It could indeed be de lens. It occured again yesterday when I was shooting with the same lens. Also got a protect filter on it:

Canon Zoom Lens EF 24-70mm f/2.8 L II USM
B+ W Neutral Clear Protect Filter 007 MRC nano 82mm

[Gary Huff]

Originally Posted by Philipp Sokolean

B+ W Neutral Clear Protect Filter 007 MRC nano 82mm

You can't get much better with a protective filter than this one. I would first try shooting with it for now (I haven't used a protective filter in five years, and I haven't had any issues. I would use them only in poor, windy conditions with a lot of fine particles blowing about, like on a beach).

See if you get the shoots again. The lens will be trickier to tell, since it seems to be a somewhat random occurrence, but removing the protective filter will be your best bet. If you don't get this issue while not using it, then you know what's up.

However, I will say that the flare issues I had with using a protective filter where more spot-like and not banded. That's not to say it can't happen, but it's not my experience.

[Chris Medico]

Hm.. The green band could be an artifact of flickering light coming in the window along with the rolling shutter readout of the C100. It looks like a photographers flash in that respect. That is what I would put my money on in regards to why it shows up as a band in that image. That is my best guess from not seeing the video itself.

I expect the source of the green band is an internal reflection between the front element of the lens and the protection filter. If you look at the front element of the lens at a shallow angle you'll see shades of that greenish color from how the coatings refract the light at those angles.

[Jim Andrada]

If the line isn't in the same place in every frame I'd be inclined to doubt that it's a sensor issue.

[Philipp Sokolean]

It mostly occurs when there is a person standing in front of a bright window. The line runs parallel with the edge of the window and moves whenever the camera moves. It's not constantly in the same place. A photographer was not present at that time... I'll try removing the filter next time I notice the line. Thanks for all the help so far.

[Chris Medico]

That is a strong indication of an internal reflection between the filter and the lens.

[Jim Andrada]

I'm pretty sure it's a reflection if it only shows up in the darker areas and moves around on the frame depending on how the camera is aimed.