Sigma Art 50/1.4 at 800+g and the Pentax at 900g for one 50mm lens. This is why the current trends for much of "boutique" full frame lens development strikes me as absurd. When you recommend such a combination, I can probably guess you don't actually own either one. The Canon 24-70 f2.8 zoom is not as heavy as the Pentax and is about the same as the Sigma and that, at least, represents 3 to 4 prime lenses. The Canon 50mm f1.2 R may be a great optical performer but it weighs 950 g. God knows who is buying these prestige lenses, but good luck to them.