XZ2 Shutter Lag
I sometimes have an issue with the focus locking on to an object when the lighting is dim, but only at the 3x to 4x end. Oddly enough, after a certain point, the darker the room gets the quicker the focus gets. When it is near pitch dark, the focus is near instant, and is accurate (I think it has something to do with it picking up the focus assist light better).
This is really not an issue for the though, because I’m coming from a sony nex 5n, panasonic fz200, and panasonic gh2, which all had issues with their kit lenses focusing in darker rooms.
A side note, if you have it in continuous auto focus, and the camera does not get an initial lock in the dimly lit room, hold it on that spot for a second and it will focus on the subject (but won’t give you a green lock box). When I have the vf-2 attached, you can see the image getting clearer and clearer and you can hear the focus working until it stops and is in focus)
Oh, also, if you by chance do not get a focus lock, you can always flip that lever really quickly and manually focus the rest of the way and get the shot.