It’s bizarre to think that a $6,000 lens is a bargain, but that’s precisely what Sigma’s brand-new 300-600mm f/4 DG OS Sports lens is, thanks to the landscape in which it exists. Telephoto primes with an f/4 aperture can be extremely expensive, way more than $6,000, and Sigma’s new lens zooms. It’s a highly appealing lens, and Sigma targets an absurdly aggressive price point.