I just did another set of measurements, as the sky conditions were different from the prior posts
Where I am, 4pm PDT, sky overhead has thin cloud cover obscuring the sun. Gray card reads ISO 250, 1/250 f/8 +0.8EV, gray card was sitting on the table in foreground
Distance sky is +2EV brighter than gray card, and far horizon there is a band of blue where the edge of the cloud cover ends, also +2EV brigher than local gray card, and the tree trunk is -2.4EV dimmer than the gray card.
As Sirius Glass mention, in this case including too much sky in a meter reading will result in overall under exposure and poor muddy colors in the shade, the tree trunk lacking detail (-4.4EV below sky's brightness), and a graduated ND would be very poorly suited for use in this scene.
This shot just taken in my works-in-progress backyard renovation. Gray card measured ISO 250, 1/250 f/8 +0.7EV.
- Shot 1 was taken at f/8 (my point and shoot's smallest f/stop). Sky is somewhat blown out, even with -0.7EV as exposed. Shot 2 is a crop of the area of the tree trunk, not much shadow detail
- Shot 3 had exposure adjusted by +1.0EV, to brighten the shadow detail yet blowing out the sky even more. Shot 4 is a crop of Shot 3 using the same crop area as Shot 2, better shadow detail
Just to illustrate the sky's influence if too much of it were included in the metering area of the camera. And the inability to apply a graduated ND.