Canon FF user (6D): Love the Z. Distagon 21 mm f/2.8, for general landscape (takes filters and a Lee 100 x 150 mm GND set-up), and especially for astro-landscape. Hard stop at infinity (woo hoo - astro-landscape photographers know this is a nice feature. I don't think that the Milvus now sold changed the optical formula, but check, I could be wrong. My copy of the Distagon 21 was bought used. Tank of a lens. Personally, I use the 21 mm a lot more than the inexpensive Samyang 14 mm f/2.8 - fewer compositions need 14 mm lens on full frame.