Quote Originally Posted by Mike Milicia View Post
The key phrase in my statement was "the area OUTSIDE your depth of field".
Yes, at a given f/stop setting, 300mm at 15 feet will have the exact same DOF as 600mm at 30 feet.
However, that says nothing about how quickly the degree of blur increases in areas OUTSIDE of the DOF.
With longer focal lengths, the areas BEHIND the DOF, will become more out of focus faster,
increasing the chances of getting a classic Birds as Art "wash of color" background.
Hey Mike, I understand exactly what you are saying but.... With a constant subject size, I think but do not know for sure, that the blur in front of and behind the "acceptably sharp parts of an image (whatever that means), would be the same. But that is what I think not what I know so I am open to what others have to say or any proof or examples that you might have.