https://www.youtube.com/watch?v=xU9gTtoNRaU&feature=youtu.be Comment on the forum The size of this optic is incredible, a world first for a full frame F2.8 constant zoom of this focal length. It beats the existing Tamron rival, and weighs just 16.6 ounces. Half the weight of the DG DN ART version. To illustrate just how small it is, here it is on the Sigma Fp! Here’s what Sigma have to say about the new zoom:…