Because of the many Dynamic Symmetry examples available online, far too many beginners are under the impression that master photographers previsualize the design grid before shooting. This, of course, has no basis in reality.
The truth is, it's highly unlikely that any photographer can visualize the full armature of the rectangle while trying to concentrate on the scene or subject they are photographing and I would be wary of those that claim they can. With that said, the goal of the photographer shouldn't be to memorize the Dynamic Symmetry grid but instead develop the necessary skills to be able to recognize a masterful image intuitively.
Below are several examples found on the internet that demonstrate the application of Dynamic Symmetry. However, does this mean the photographer attached design grids to their camera or pre-visualized the grid before shooting? Absolutely not. To learn more, see the article Dynamic Symmetry for Photographers.