![Amazon.com : Sigma 120-400mm f/4.5-5.6 AF APO DG OS HSM Telephoto Zoom Lens for Nikon Digital SLR Cameras : Digital Slr Camera Lenses : Electronics Amazon.com : Sigma 120-400mm f/4.5-5.6 AF APO DG OS HSM Telephoto Zoom Lens for Nikon Digital SLR Cameras : Digital Slr Camera Lenses : Electronics](https://m.media-amazon.com/images/W/MEDIAX_792452-T2/images/I/61OgMl39sfL._AC_UF350,350_QL80_.jpg)
Amazon.com : Sigma 120-400mm f/4.5-5.6 AF APO DG OS HSM Telephoto Zoom Lens for Nikon Digital SLR Cameras : Digital Slr Camera Lenses : Electronics
![Am I hearing things? Today I recv'd this Sigma 120-400mm 1:4.5-5.6 APO DG OS HSM lens with a Nikon mount. When in AF mode I can hear what I think are gears Am I hearing things? Today I recv'd this Sigma 120-400mm 1:4.5-5.6 APO DG OS HSM lens with a Nikon mount. When in AF mode I can hear what I think are gears](https://preview.redd.it/br379tqide051.jpg?width=640&crop=smart&auto=webp&s=24c6a590d8943177cebef82ed4b62a7942473438)
Am I hearing things? Today I recv'd this Sigma 120-400mm 1:4.5-5.6 APO DG OS HSM lens with a Nikon mount. When in AF mode I can hear what I think are gears
![Amazon.com : Sigma 120-400mm f/4.5-5.6 AF APO DG OS HSM Telephoto Zoom Lens for Canon Digital SLR Cameras : Digital Slr Camera Lenses : Electronics Amazon.com : Sigma 120-400mm f/4.5-5.6 AF APO DG OS HSM Telephoto Zoom Lens for Canon Digital SLR Cameras : Digital Slr Camera Lenses : Electronics](https://m.media-amazon.com/images/W/MEDIAX_792452-T2/images/I/71zCzqCWY5L._AC_UF894,1000_QL80_.jpg)