The sunny16 rule and all light meters for that matter work on 50% gray. They are always trying to bring the exposure in the the middle ground. I remember one of the first thing I learned in photography was how to fool the camera into making snow look white. On a snowy day, the meter will read the bright white and try to bring it down to middle gray and in doing so turn the white snow into a dirty and muddy looking mess.
This is basically whats going on in the first post. Sunny16 is making the bright part of the image middle gray in doing so underexposing the shadows. Look at the pavement in the road. It's right on. The road is overexposed in the one you called the correct exposure. It sunny16 rule worked in your second test because of the diffused light of the overcast day and the overall lack of contrast. Sunny16 is just a guide and you, as the photographer, need to adjust exposure according to what you want the photograph to look like.
This is basically whats going on in the first post. Sunny16 is making the bright part of the image middle gray in doing so underexposing the shadows. Look at the pavement in the road. It's right on. The road is overexposed in the one you called the correct exposure. It sunny16 rule worked in your second test because of the diffused light of the overcast day and the overall lack of contrast. Sunny16 is just a guide and you, as the photographer, need to adjust exposure according to what you want the photograph to look like.
