Please do not let unsettle. The focus is fast enough. I also own the f1: 8 and realize there is no major difference.
Also, the AF sits. But those who tried this on small parts or less contrast subjects at close range in low light, should rather focus manually on tripod. On the colors of the white balance reacts with f1: 4 depending on the environment a little 'stronger.
Do I need reserves in the exposure time at fast moving objects, hand-shake, or will preferably take pictures in low light, this F1: 4p a steal as wonderfully easy, universal and compact 'Fortune Cookie' for the price. In the glare of course recommend a pole or neutral density filter.
However, note must be fair to say that the difference with the F1: 8 is not particularly striking and strong in the bokeh from the respective background-dependent. Of course, not as nice as on a high-priced prime lens with z.Bsp. long focal length and high luminous intensity.
I mean, of course it is always better and thus more expensive.
