Is That a Bug In Your Lens?

High-end camera lenses are usually sealed against dust and moisture. So how did a fully grown fly get inside a $2,000 Canon F2.8 70-200 mm. telephoto zoom? That's what the folks at Lensrentals would like to know. 

It took a technician several hours to disassemble, clean, and reassemble the lens. What I found most remarkable about the story is that the fly wasn't even noticeable until the lens was stopped down to F13, when it started to appear as a dark smudge.