Lately, I've been noticing two or three spots on various videos, usually appearing in the same place. They look like they might be caused by something on the lens, except they seem to be in pretty good focus, so I don't think that's what's going on.

The weird part is that they seem to come and go; I just checked two videos which were shot minutes apart, and they're plainly visible in one but not visible at all in the other. Also, in one of the videos, a spot seems to appear out of nowhere just before the video ends.

Has anyone else seen anything like this? Sensor problem perhaps?

Thanks,

Scott