5D MKII w/ Light spot in center of frame

Hey all. First time post here. We're a company that deals mainly in professional video cameras but on occasion we get 5D Mark II's in. We recently sent a camera to a customer and this is the footage he's getting off of it, regardless of lens used. The video cameras are my specialty and we've never seen anything like this on one of our video cameras, even the CMOS cams. This is what he sent me:

http://vimeo.com/43148​531

http://vimeo.com/43148​530

I imagine that's not something on the sensor since it's lighter in a dark area of the frame.

So what am I looking at? Is this a failing sensor? It stumped me right off the bat and I couldn't seem to find anyone else with similar symptoms.

Well this is a bit disheartening. I was under the impression that this would be easily identified by the community. Does anyone want to take a guess?

Has anyone seen anything like this before at all?

Never seen this before. Any chance the customer poked the sensor with his/her finger and left a big greasy smudge (although I think that would make a dark smear, not a light smear).

Only other thing I can think of is maybe it's some sort of light leak.

Looks like a gob of something on the lens... And for it to register, it had to be huge!

Can't believe your customer didn't see that.

My initial thought was something on the lens as well but it's showing up as a light mark against dark objects which makes no sense.

I was thinking it would need to be a smudge on the sensor or something on the lens but he says he's put two lenses on it with the same results. I believe those two links are of different lenses.

Note that you are shooting into the light. My guess is a cheap filter on the lens or reflections internal to the lens. Could even be a reflection off the sensor. Does it disappear when NOT shooting into strong front lighting?

Thanks for the help guys. It's a problem that happens with different lenses so whatever it is it appears it's a camera issue, not a lens issue. That's why I suspected a bad sensor. I've asked him to get me low light shot and a shot outside in the light.

I also asked him to lock the shutter up and see if there's anything obvious on the sensor.

Alright guys, this is the latest vid he sent me. Notice it doesn't appear in the light... Is it safe to assume we're not dealing with dust or some other foreign object on the sensor? Every time I've seen that it's visible in light shots and here we're not seeing anything in the light shot...

https://vimeo.com/4327​2328

I've requested a video of a completely dark environment so I can eliminate light leakage as an option but assuming we're still getting this in a completely dark room, would a bad image sensor be a likely cause here?

Hey guys... So latest update on this. He just decided to tell me that this only happens while in video mode. The artifacts in those videos do not appear in still shots. What can I make of that?

Has he looked at the sensor with a lighted loupe, you should be able to see something maybe under the AA filter, or some damage to the sensor itself.

You'll notice at 0.6 seconds in the vid there is a "u" shaped mark on the pot, that can be still seen through the hazy spot, so the sensor is still picking up the detail, which leads me to believe it's something in the light path to the sensor.

If you believe the sensor is at fault has he tried remapping the sensor , by doing a manual self clean with the body cap on for about 2 minutes ?

If I have to hazard a guess, then something tells me that someone aimed the camera in live-view/video mode on a very bright light source (possibly the sun) for an extended period of time.

looks like a water spot on the aa filter o. Top of the ensor. Maybe someone tried using the clean with your breath technique and missed a spot on the sensor. Only way to find out is if you look at the sensor under a light.

it shouldn't affect stills because waterspots blend with the background.

First off, thanks to everyone for the help. I got the camera back today. Guess what... no signs of any issues at all. Nothing. So I email the customer again and again ask him if he used the lens that we included or other lenses. This time he says that he DIDN'T use the lens we included and instead used the following (image below).

He says they're still lenses from his Canon F1. Are these lenses designed to work on the 5D's full frame sensor? Now that I know it's not the camera it does look like a light leak and if it's appeared on both of those lenses then I'm likened to assume they're not compatible with the 5D or that his adapter has an issue. Anyone else want to speculate?

Those are FD lenses, from Canon's pre-EOS camera systems, used with an adapter. I have never tried such a rig but, depending upon the quality and condition of the adapter, I suspect that this could cause any number of problems.