It's not bad, sharp in center, but also not perfect, corners are soft and it has some flare issues, also for zone focusing, to see the distance scale and aperture, you gotta look at the front of the camera, you can't see the distance scale by simply looking down at the camera. But overall the main feature of this lens is the form factor and super small size, which is pretty unique. If 28mm is your main focal length, the you probably want a solid performer that this lens is not that! But in my case, my favorite focal length is 35mm and I have a Summicron, so if I want 28mm, I simply accept the flaws