As a professional photographer, I have used various lenses throughout my career, but the Sigma 150-600mm Contemporary Certified Refurbished lens has exceeded my expectations. Its optical performance is spot on especially for my wildlife photography work. The stabilization is top-notch, which comes IN handy with long zoom shots. The only downside is that it doesn't come with a carrying case, so i had to purchase one separately .Nevertheless, considering its affordable price, I would highly recommSee full review