How does my Casio compact determine the amount of flash?

I have a Casio EX-Z60. It is about a year old. Cost was about 200
dollars. http://preview.tinyurl.com/2g2dts


How does such a camera determine how much flash power to use? The
result suggest that there is some sort of intelligent control going on.

(1) Is there a detector which senses the amount of lght reflected by the
subject and then in the middle of a flash it stops any power it does not
want?

(2) Does the camera determine how far away the subject is and then
calculate the amoun tof illumination needed based on distance, stop
number, sensitivity setting, etc.

 

Hi,
You sort of answerd your own question. Ever dealt with olden days
Thyristor flash, guide number, coverage angle(H-V), etc.

 

But where would the high speed sensor be to detect the reflected
light and cut off the power to the flash?

In those days it was unusual to have an electronic focus. Now we
have it on every compact digicam then that makes electronic focus an
alternative to determine flash exposure.