[Rover]

It's contradicting the intended use: any f/1.4 lens I own, I bought to be able taking pictures in dark places. If that means, I have to use LV and focus manually because PDAF cannot deliver the necessary accuracy then why bother about f/1.4 lenses in general? For fast wide angles it's much tougher to get a precise AND quick AF.

 

I already compared PDAF with CDAF on that lens, there's no single picture when PDAF was more precise although I did AFMA - what else can I do?. To do AFMA, you need to be really close at the target: 20 mm × 50 = 1 m distance, but what about infinity and what about those big AF points which leave me totally in uncertainty where this thing will focus?

Your demands are elevated indeed. I know my 24/1.4 L is mediocre for AF accuracy in the dark unless I'm using it at point blank range (and even then...) Serves me right for trying to shoot distant subjects below f/2. The 16-35/4L IS is sometimes a better choice... despite being 3 stops slower, it seems to have a much greater hit rate. The shutter speed is the only concern in this case.