Akul, regarding the back focus issue on the 21mm, I did not use the focus confirmation dot to determine the focus in my test. I have carefully tested it by using the viewfinder and my eyes to make sure that the focus is dead on. After I take the shot, the focus on the image is behind where I focused. I was thinking it might have been an error on my part, but after extensively testing it indoor and outdoor, I was able to confirm that it was off. For example, when I was shooting at 2.8 of trees in front of me, the foreground tree was blurry while the tree behind it was sharp. I did not have this issue with the 100 ZF.2.
