This is a Canon EF 80-200mm F4.5-55 zoom lens which had water damage/mess on the internal lens elements. Other than grubby lenses this lens work fine so should be simple to fix! First thing to to is take off the rear mount. There are 5 screws on the back plate and 2 hidden ones which hold the connector contacts in place. The mount twists as it comes away. The AF/MF and tricky to get off and real pain to get back on so engages with the mechanism. The screws are #00 Phillips and pretty poor quality. The lens already had a head snapped off one of the rear screws and 2 rounded off inside the lens from someones previous attempts to take is apart. One the tabs are pulled back the connectors pull out and the board comes away. Underneath is the AF motor mechanism, this is held on with 2 screws and simply pulls out. The rear lens element simply unscrews and comes out. Under this is a random springy piece of metal (which I assume this helps stop the rear element unscrewing). The next element is held in by 3 silver screws with a large diameter head, these screws are very poor quality and very easily rounded. Next the front end of the lens is dismantled. The ring at the front of the lens just clips out - there is a small notch to insert a screwdriver. The front element then slides and comes off. There is then a black cover piece which sits in front of the aperture mechanism held on by 3 screws. |        |
I didn't bother taking off the aperture mechanism as the ribbon cable is threaded right through the body to the board at the rear.
Now we can access all the elements to clean them - there is still one element in the lens but this is easy to reach.
Assembly was pretty simple apart from getting the AF/MF switch back in the correct place. The construction of this lens seems pretty cheap and flimsy, it wasn't obvious how to completely strip the lens but I assume there was clips etc.
