EOS-1D X Mark III Dark curved line in live view

[Corvalan]

I have a Canon idx mark 3 camera.

In Live View, I see a dark line on the image.  When I take the photo, the dark line also appeared at the exact location.

I cleaned the mirror and still it is there.

I believe it cannot be the sensor because I see it Live View.  I also cleaned the sensor, just in case, but the line still appears in Live View and in the photo.

What could it be?

[jrhoffman75]

"I cleaned the mirror and still it is there."

The mirror is out of the image path during Live View and taking a picture, so that is not surprising.

"I believe it cannot be the sensor because I see it Live View"

When you are in Live View you are looking at exactly what the sensor sees, so if something was on the sensor you would see it in Live View.

Can you post a screen shot of the image that shows the line?

Is it a distinct line or a fuzzy line? If fuzzy, is there perhaps a thread or something in the mirror box but not on the sensor?

Does it show with more than one lens?

[Corvalan]

Thanks for your response.

it happens with all lenses. In Live View, the line is kind of light gray and diffused. When o take a photo with f22, the line is sharp and darker. When I take a picture fifth f2.8 the image look similar to the LiveView image, thicker, diffused and lighter. 

[jrhoffman75 · Accepted solution]

When you say you cleaned the sensor do you mean you manually cleaned it using a blower or perhaps a sensor brush? If so, that should have removed anything right on the sensor.

Look for a hair or something inside the mirror box but not directly on the sensor.

Maybe hanging down from the front of the mirror box where the mirror flips up.

[Corvalan]

I took a closer look to the sensor with good lighting and I saw a hair.  I got rid of it with an appropriate brush and blower.  Now, everything is working gooooood!

Thanks so much.