I'm a beginning photographer. It's just a hobby. I've been taking high school sports photos because I'm a teacher at the school and photoshopping sports posters for parents to upgrade my equipment. I bought a non-os sigma 70-200 f2.8 lens on eBay before I knew a lot about what I was buying. To my untrained eye and the parents eyes, I think my pictures look pretty good. I'm wondering if I should sell this lens though and upgrade to the OS version? Is it better? I shoot at a fast shutter speed to stop the action so I'm not sure if the OS would even be beneficial. Just wondering what others thought.