Your Camera has a built in light meter which it uses to try to expose your image as you already know

as your reading your books. There are different metering modes and your camera does the same thing in all modes which is try to make everything average... soo sorry if im repeating here lol
To use the zone system by adams all your doing is to find an average colour in the scene which are usualy Green Grass, Blue Denim Jeans, Postbox Red, Some skin tones like Asian Skin Tones. And then you set your camera to spot meter and meter off the average colour exposing it to be 0 this is easier to do in manual mode as in other modes you have to set the EV adjustment...... Ohhhhh and when your done dont forget to meter your highlights and check there not going to blow out
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You cant fool all of the people all of the time, some of the time all of the people will some of time but not all of the time as some of the time all of the people will some of the time but all of the people will not all of the time

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