The conscious deciphers the images it sees. It will fill in much of the blanks and make assumptions of temperature, texture and distance, a conscious image of what it sees with cues of what it remembers. The problem with drawing an image is that most of the time the conscious naturally takes over the process and draws what it thinks or assumes it sees and not what it actually there. Some aspects of depth and texture might need to be exaggerated by the artist to convey the distance or texture since we transfer a three dimensional image that is real to a flat image that is obvious to the brain that it has no depth and no actual temperature. These visual cues are how the artist or the photographer captures the illusion of the image and explain to the viewer what they should expect of the image, these cues will hopefully be subtle but that is up to the artists style and intention.
An aspect of photography is directly related to this process of explaining to the viewer what they should feel or see when they see a flat image. On one of our trips I explained to my son that the reason his photograph seems flat and bland compared to what he saw is the fact that he left out the visual cue that would explain what he saw. The camera automatically is trying to create an even grey value of the image, mix this with the fact that there are no cues to explain distance and most point and shoot cameras shoot with a wide vantage point-the image is destined to be flat and bland unless the photographer adjusts and creates the cues needed to convey the space-the palette of the artist is not much different than the artists'; proportion, value and change in texture all explain to the viewer what they are seeing ad how it should be interpreted by the eye and the brain-the illusion of a sweeping canyon or the endless ocean scenery, even though the image is a flat, non-dimensional image. Once he used images for proportion and adjusted how the camera saw the value of gray-suddenly he had a photograph he was proud of.
Beside the basic loss of depth and dimension the artist has to work with, the fact that the conscious is trying to fill in what it thinks it sees which means the actual image is not capture correctly but is almost like the very abridged version of a novel where all the main ideas are left out. My best example of this is the rendering of droplets of water-on first notice you would over complicate the process and yet the image is very simple- a block of dark color that the droplet is on and a transparent area that is lighter than the object, add a highlight of light and the droplet is complete. As artists we must capture what we actually see instead of allowing our brains to ignore the actual the eye sees and fill in the blanks with a conscious attempt at seeing.
A challenge- go and look at a field that is on a hill and try to explain why the hill looks like it descends-how would you capture the image and explain that the field dips down when all you have is a square flat image to work with. Another great example would be to look at a road and capture it in a view finder-realize that miles are capture within a square that is very small-what makes the road appear to be long and expanse when it fits within a small area when view through a viewfinder. Looking at a landscape this way will help in drawing and photography. I hope this was helpful.