'Being a photographer means living your whole life subconsciously considering the light'.
David Noton (Waiting for the Light)
This is especially true of landscape photographers. And when the landscape is actually a seascape, dealing with the light in the sky as well as the light reflected off the sea means one becomes even more conscious of the subtlest of variations in the light, to the extent that the optimum moment can be very easily missed. The key word in Noton's statement is 'subconsciously' because it implies an intuitive response to the light and its changes has been built up over the years like a series of memories against which current conditions are compared and assessed.