I recently got a pair of very good Porros, the first I´ve had for over 25 years. They´re Nikon EII´s. Having tried them in the field now, I´m stunned by the DOF, and by the "punchy" three-dimensional effect, which is more marked, I think, than in the best of my roofs, a Swaro EL. I´m not saying the porros are better in all respects, but I´m just wondering is the 3-dimensionality and DOF thing a feature of porros in general, something to do, maybe, with the objective lenses being wider apart?
Our ability to judge distance and percive 3D is because both eyes observing the same object but from slighty different view points. With the lenses of porros being further apart than your eyes this does make the 3D effect for more pronounced. I have a pair of 8x30 Nikon E's (even wider FOV than the EIIs), they are optically as good as my Swarovski 8x32 ELs...
I'd love to see the 3D effect that you get with a pair of donkey ear binocluars... if only I could find a pair to try.
The experts will say that depth of field is only a function of power. We can't change aperture in binoculars like you can in cameras, and use longer exposure.