has anyone else in here ever experienced this:

(and i guess this might not exactly be an xl-1 issue but since i shoot with the xl-1 with the standard 16x lens)

but when i first got the camera i got a few filters to go with it... uv and warming. while i was playing around with footage i had shot i noticed something dark in the bottom left hand corner of the screen, what i thought looked like a hair. it drove me bonkers for a couple of hours cause as far as i could tell every part of the lens and camera were clean, until i realized i had put the warming filter on top of the uv filter. so i took both off and the dark "hair" was gone. so i was satisfied that i had just extended the rim of the filter into the cameras view...

but now while editing a short i shot with only one filter attached i think i am noticing the same thing. not near as pronounced as before but still on certain shots, ones with light, muted tones filling in the bottom of the screen i seem to be noticing what looks like shadows.

what could be causing this? is something inside my camera causing this or how the lens attaches or, in the lens?

Where did you get these filters? Who makes them, are they Hoya, Tiffen, Canon or some other brand?

they are tiffen and i got them at b&h.
they are 72mm.

chris, you seem to be leaning toward the filters as the cause. if that is the case why would the, is it called vignetting, occur in only three of the four corners?

I was curious about the filters because if they were cheap no-name jobs then that might be the problem. But since they're Tiffen, I doubt that's the case. We need to get a filter expert in here... I'll see if I can find one. Meantime this issue is wide open.