Dust is everywhere in the environment, unless one lives in outer space. It is impossible to find a used lens without dust, and even new lenses have some dust. Dust is out of the photographic plane and simply will not affect a photograph.
Canon 35-70 Auto Focus zoom lens. The focus and zoom in both manual and Auto modes works perfectly. all Canon EOS SLR cameras - film or digital, without exception. Will this fit your camera. T he aperture blades are nice and snappy with no drag or catch.