Whilst out with the camera today I wanted to try and get some milky water.
Everything was blown out, even when stopped down to F22 and 50.
I then had a brain-wave, put my hand over the top half of the frame for a few seconds and only expose the bit behind my hand for a second. The result is below - I know its not a great image, but the water below where my hand was is (almost) milky, and the sky isnt too blown out. The clearly visible line in the water was the shape of my hand.
Now, the question is this... Is this essentially what an ND Grad does? Im pretty sure it is, obviously it does it in a much more gradual way and the line between and dark on the filter will be straight!
Only asking as Ive read a lot about them and often get myself confused between Grads and ND Grads.