Assertion: camera's lens | /r/HasProperty | removed
Facets:
Source sentences:
text: Almost all contemporary SLRs use a focal-plane shutter located in front of the film plane, which prevents the light from reaching the film even if the lens is removed, except when the shutter is actually released during the exposure.
text: Because many SLRs have interchangeable lenses, there is a tendency for dust, sand and dirt to get into the main body of the camera through the mirror box when the lens is removed, thus dirtying or even jamming the mirror movement mechanism or the shutter curtain mechanism itself.