Massive construction, fast autofocus, optical quality bewildering at full aperture, beautiful background blur in summary this goal is a wonder! Given the very low depth of field at f / 1.4 and the great sharpness to this opening, we see easily that the autofocus micro-adjustment may be necessary. If your EOS allows housing, it is set in minutes for a test pattern (LensCal Spyder) or a printed page placed sideways; otherwise the Sigma dock allows for this setting through the lens. It is not a manufacturing defect of the lens, my 85 / 1.8 Canon as it takes advantage of a small adjustment to f / 1.8. Small tip, the EOS 70D makes up a very sharp focus on the sensor in LiveView, just compare identical views taken through the viewfinder and LiveView whether a AF adjustment is necessary.
