I had the 150 Macro lens on the 70D for a few months whilst the zoom lens was on the 60D . I was doing regular photography with the 60D , and today decided it was time to put the 150 back on . I went out took a few photo's and ?? it looked like the inside of a vacuum cleaner .. There was particulate all over the image ( something on the sensor ) ... Taking the lens off and setting the camera to manual clean ( lifting mirror ) the first thing I noticed was the rubber coating on the inside peeling .. ( About 3 different locations ) SO apparently every time the mirror lifted it hit the rubber coating causing more particulates .. WTF Canon ! So I spent all afternoon peeling off the lifting rubber coating .. Then cleaning the sensor .. Its reasonably clean now .. I put the zoom lens back and will take some shots to see if it becomes like the inside of a dust buster again . How does that go ? Not Happy Jan ! In this case , Not Happy Canon .
Rubber doesn't normally breakdown that fast, it can be accelerated by extreme temps, humidity, chemicals, etc... Still the body is only a couple years and hard to believe. Even out of warranty it wouldn't hurt to call canon since it seems the rubber was likely defective from the beginning.
I got the camera used a few years ago .. So don't for a moment imagine it has warranty .. The first year it ran fine and was relatively clean ( sensor ) Still runs fine but the last 12 months I did notice more rubbish on the sensor .. Switching to a normal zoom lens , the junk does not show ... That was 6 months ago , so a week ago or so I put the 150 back on the 60D in preparation for spring .. And WOW ! .. Removing the lens showed the rubber peeling .. Looking in from the front , the front edge where the mirror rests.. And the rights side of the interior @ 2 locations . Bottom and there is a hole for a small lever .. So every time the mirror lifted if would have hit the peeling rubber on the right side .. And coming down possibly hit the rubber @ the front edge . Not sure Canon can do anything about it , maybe just clean it more thoroughly than I could ? But I got it relatively clean , ?? if it stays clean .
Well if the rubber was faulty they may replace it or offer a deal on replacing it so that would hurt to try. Changing lenses would have no factor other than introducing extra air flow into the camera that could have kicked up and blown around the particles. You mentioned hitting the rubber on the front or sides, maybe the mirror is loose or not aligned correctly and needs servicing, it should move up and down without making contact with anything, the only exception is where it rests against the top when the mirror is locked up. If the mirror is scraping the rubber that would explain why the problem as progressively got worse. Obviously without actually seeing the issue and playing with the shutter this is just a guess based on what you have described.
Its the lose rubber - it stuck out far enough to make contact with the mirror ... So every photo probably created more rubbish inside the camera ... When I changed lenses , the mirror was down so I noticed nothing wrong , till I put the Sigma 150 back and saw all the rubbish showing up in the image .. I still haven't used the 60D ... I need to take a few hundred photos and see what happens ...
I still haven't taken any pictures But you can see the rubber (?) coating is fine on one side , but I removed it from the other side . As well the bottom ... This is inside the camera , inside the area behind the mirror and surrounding the sensor
Well I still think there was probably an issue with faulty adhesive, which would be on canon. I still think it wouldn't have hurt to reach out to canon in the first place and see if they would have replaced and cleaned up the issue. I still would call see what they say since the rubber coating peeling off should never happen in normal use. That is a big mess of sticky debris in there and I'm sure with the right cleaning solution (maybe with some alcohol in it) the rest of the surfaces could be cleaned up spotless. Canon would have the right stuff to do so. I actually would want to send it to them not just to get it cleaned completely but to get a new piece of rubber put on, you can see in your photo that the surface is reflecting light which I wonder how much impact that could have on the images. The worst they can say is they wont touch it since you tried to do some of the cleanup yourself. I would hope they would at least offer a reasonable repair quote to have rubber replaced and thoroughly cleaned.