Visual perception, or the ability that allows you to observe a certain situation, is shaped and molded by you and your experiences in your surroundings. The way you see things, observe, take note of details and so forth defines your visual perception and how detail oriented you are.
Let us take a neurosurgeon for example: his visual perception is highly tuned towards details. The surgeon should be able to notice things which regular people wouldn’t even be able to see.
Psychologists, on the other hand, should be able to catch various micro expressions by the people they are working with in order to be able to help them; their visual perception is highly tuned towards noticing small differences in the facial expressions, which often occur for a split second. Along with this, they should also be observant of the bigger picture.
Us photographers are a different breed. Our visual perception is separately tuned towards different things that we are supposed to observe.
Though it's very difficult to fine tune your perception for light, this is something you start doing right away. Due to the limitation of the camera (the amount of light it needs to generate a decent picture) you first start evaluating the amount of light you have and whether it is hard or soft.
Generally, you do this by trial and error. First off, all you start with sources you're familiar with e.g. fluorescent lights – and you generally learn which settings work in that kind of a setup, this can then be used in other scenarios.
You can ascertain whether the light is harsh or soft by looking at the shadows and observing their shapes i.e. whether closer or further away from the light source.
Photo by Takashi Hososhima
After you’ve learned how to judge the amount and type of light, further down the road as your visual perception develops (which will come with experience), you’ll start noticing even more things. For example, the way light forms around shapes with more complex setups (even more light sources), as well as noticing reflections too e.g. water and eye catchlights.
Once you enter a room, you won’t be able to stop yourself from judging it as a possible photography location. Within a split second you’ve already judged the light and now your mind focuses towards the special features. For example, whether there will be enough room for a subject, or whether there is already a subject worth taking a picture of.
You’ll also start noticing the colors: whether they are complementary or not, or if they are suited enough for what you usually shoot.
Photo by halfrain
Then your eye will turn towards the smaller details, like textures, walls, reflections off the textures, the direction from which the light is coming from, how it will affect the foreground, background and so on. Can you now see how your mind is adjusting according to what you see as a photographer?
As long as your eyes are open, you’ll be evaluating the artistic elements in every scenario you will find yourself in. Whether it will be the rule of thirds all the time, or the guiding lines when you are walking down the street, your brain will fine tune your visual perception to be suited for photography.
Everything you know and learn about composition and artistic elements will be burned into your visual perception, which is why you’ll become more and more efficient with practice, and after a certain point it will come to you naturally. This is also helpful for the pre-visualization process.
Patterns are something that will catch your eye every single time. This is due to the fact the brain is wired to notice patterns by default, that is how we navigate and for some reason, it is soothing for the brain itself. So, add the creative uses on top of that and you have a combination that will “haunt” you one pattern at a time.
The more you “do” photography, the more your brain adapts to it. That is a natural process, and it's exciting. Except for when you really need to analyze deeply!
Fear not, because it shouldn't be stressful. It is something you’ll start doing mechanically, without even thinking about it, so it won’t tire you nor distract you from anything. It will just be the way you see the world.
The only downside I can think of is that you’ll be noticing every single mistake done in photography and film, ever. Often, you’ll find yourself laughing at some scene in a movie where you’ll notice the green screen stitching, or when the light won’t make any sense.
But you get used to that too, and then you’ll start appreciating film and photography even more when you realize how complicated the creation of a piece of art is.