Although I do not own the Sigma 20mm 1.8 lens myself I can only assume that there must be some quality control issues with it judging by the conflicting reviews that I am seeing. I have seen a lot of people complaining about how soft this lens is while others praise it for being sharp. This is why until I have a chance to test out the lens for myself I will reserve my judgment about it. I know that Sigma typically makes quite sturdy lenses so I am not too worried abut the build quality but the optical quality is still up in the air. A lot has been said about the Sigma being one of the fastest lenses in its focal range, which makes it an attractive option, but if it really is as soft as people say I will have to pass on it. I am waiting for the camera shop in the mall to get this lens in stock so I can see for myself.