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It is an awesome lens ... with a similar awe-inspiring price tag. In relation to other lenses in this class, the performance is already superb at f/1.2. Yes, the outer image region is not truly stellar but it's impressive nonetheless. The image quality is extreme at medium aperture settings - across the image frame that is. Low lateral CAs contribute to the very high image quality perception. Image distortions are generally no issue [...] The bokeh is very good.