I just purchased a used Canon EF 70-200 mm f/4 IS lens. Appearance-wise the lens is in perfect condition, as it should be, as it was sold in "D" condition from Adorama. The autofocus mechanism seems to work fine, but I hear a quite audible motor noise when I half-press the shutter button. This goes away after a couple seconds, and it doesn't happen if I turn image stabilizer off. Is this normal? I haven't taken any shots. Should I return the lens?
Thanks!