Hmmmm...... I was expecting you to say that you were shooting in bright high noon sun with lots of deep shadows.... Sounds as if opening up/increasing exposure by one stop in this case would have helped. Not knowing your camera all that well, I would say it is probably normal for the EV reading to change after you meter off the grey card. Because now it's looking at the actual scene you intend to photograph and that is what it is now reading.....

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