Children's Crayon

[ggroess]

Fritz,
Meters can be fooled in many wonderful ways...

Anytime the meter is given a large area of one light intensity it will get half of the exposure wrong.  yours is a good example of that.

Depending on how you have your camera set up the meter is either trying to average the entire image or it is averaging selected points in the frame.  Either way it is trying to make what it is "seeing" into 18% grey.  so in the case of your White Card...It sees mostly White...So it trys to make it Grey...

It adjusts the camera so that the majority of the exposure created has 18% grey.  That is why you should meter your subject not the entire scene.  Auto exposure is good for "average" images but in specific situations it fails to account for subject material. Backlighting is a classic example of this....

Greg

[mikemeister_admin]

Thanks, Greg!
I have often readed such things, but never interpreted on my own doings!
So, I will give it more notice.

frits