I've heard that some of the Canon cameras, including the 5D, occasionally have a problem with lubricant coming off the mechanicals and getting on the sensor. It appears I have got the granddaddy of this kind of problem.
Within the past month or so since I got the camera new I've had to clean the sensor several times -- not because of dust but because of tiny smears that magically appear. I must have spent $100 on various swabs and pads and other Visible Dust concoctions -- and I've never been able to get the sensor completely clean. There are always faint blobs somewhere (and yes, I've followed the directions to the letter.)
I also bought one of those mirror chamber cleaning kits and did that as well. But no matter how clean I get the sensor, after shooting a hundred or so frames new blobs appear.
Since I haven't been changing the lens (I leave the 24-105 on all the time) I'm sure the problem is not from the outside.
I'm going to send the camera to Canon to have it cleaned. But before I do I'd like to know if anyone else has had this problem and, if so, how did you handle it?
Thanks.