After reading this post, I tried with the 35mm F1.8. The camera is set to Aperture priority.
. When the switch on the lense is set to M/A, that is autofocus the camera does not fire till a focus is achieved. That means no go at less than 11.5 inches for this lense.
. When the switch on the lense is set to M, that is manual focusing, then it fires immaterial of the focus conformation.
I have notice even my kit 18-55, takes a lot of time deciding on whether to fire or not, when I am shooting flowers up close. If I am too close, the green light flashes and the shot is not fired. If I am at the border, it takes time, I guess just when I have shifted a bit it fires.
In a way it is good thing that the camera prevents shots which are not in focus. That means that if while handling the camera, you press the button inadvertently, chances are it will not fire. A good safety feature.