No doubt, previsualization is a fancy word, however, it is an important step during my creative process. It literally means seeing something before creating it.
As an artist, the previsualization step must occur before I reach for my camera or lens. It is the step in which I get an idea or see a mental image of what I would like to create, using the landscape as a prop and the camera as a tool.
Previsualization is not a term exclusive to fine art photography; it is used in other creative endeavors and professions. An architect cannot draw a building without first seeing the design in her mind. A programmer first learns about the problem that needs solving before writing source code. A lawyer writes his legal brief only after first understanding the case law. Similarly, you need to see the screw to know whether you need a flat head or Philips head screwdriver. Before driving your car, you must know your destination. A doctor must make a diagnosis before performing surgery. These are examples of previsualization and it is not any different for the fine art photographer; previsualization is seeing the final photograph before making exposures with a camera. As a photographer, I need to know what I want to create so I can use the correct lens, shutter speed, aperture size and filter.
It took me over a decade to finally begin previsualizing my artwork; until that time, I was more a camera operator than an artist. It also was not a lightbulb moment; it was a gradual experience in which I noticed some photographs began occurring pre-visually. Today, after nearly 40 years of making photographs, I wander the landscape without a camera until I know what I want to do; I am constantly imagining new ideas and fluidly previsualizing.
Knowing the definition of previsualization and being an accomplished fine art photographer are two different things. If you want to transition from camera operator to artist, previsualization is a process I recommend learning more about; an excellent and detailed analysis can be found in Galen Rowell's Inner Game of Outdoor Photography.