Sunday, February 13, 2011

Bringing Depth to Your Images

Chinstrap Penguin Colony, Deception Island, Antarctica
We see a world with depth because our two, forward-looking eyes each perceive a slightly different picture. Our brains merge them together to form a three-dimensional interpretation. It is the amount of overlapping information that each eye perceives that is the secret to our depth perception. It would not work nearly as well if our eyes were placed more on the sides of our head, say, like a horse, which has traded strong depth perception for a much broader, wide-angle view. However, an animal with forward-looking eyes, like an owl, has excellent depth perception.

Close one eye and your depth perception is almost non-existent. Try it. Hold a pencil out in front of you in your left hand with the tip pointing towards your right. Now try to touch the tip of the pencil with the outstretched finger of your right hand. Yes you can do it, but you might miss the first time or two.

What’s the photographic connection? Most cameras only have one eye. (Stereoscopic cameras have two.) They cannot perceive depth. When we look out over an inspiring landscape with our eyes, the sense of distance and perspective is self-evident. When we make an image of it with our cameras, something very important is missing: the sense of depth. That’s why you need to help the camera simulate a sense the depth by using one or more simple techniques.


First, though, it helps to be aware of the effect of light on depth. The more intense the light, the greater the tonal contrast, the stronger is the sense of depth. Soft, diffuse light reduces the sense of depth. Light direction also has a bearing. Frontal light, coming from behind the photographer directly on to the subject, reduces the sense of depth, whereas light from the side enhances depth. Backlight, coming from behind the subject towards the camera also can enhance depth especially when foreground objects are silhouetted. Warm colours act as though they move forward while cool colours recede. This is one reason why the person in a red jacket tends to have prominence in a photo. Now for the techniques.

Foreground, middle ground, background


The strong foreground serves as a stepping stone into the image.
Many shooters will see an inspiring scene, photograph the middle ground and background and then look at the disappointing result that lacks any sense of depth. They missed a key element: the foreground. Compare the creation of this kind of image to writing a story. Any story needs a good beginning, middle and end. So does this kind of image. Whenever I’m in this situation, I look for something to serve as foreground interest, something that can work like that first stepping stone into the scene. When you include all three elements: foreground, middleground and background, you simulate a stronger sense of depth.
  
Scale


Our dog, Thule, imparts a sense of scale to frame.
Objects look smaller the further they are away, right? But our minds know that they are not actually smaller. So when we place an object of known size in a scene, say a car or a human figure, it immediately helps the camera to simulate depth. We know roughly how large a human figure is, so if it is tiny in the frame, we know it is far away, large and it’s near. Wide-angle lenses exaggerate depth since foreground objects appear so much bigger than background objects. Telephoto lenses, like binoculars, tend to bring the background forward and appear to compress an image from front to back. They reduce the sense of depth in a scene. A strong telephoto lens can make the background appear as though it looms over the foreground almost eliminating depth altogether.


The use of a 400 mm telephoto lens causes the distant mountain to be "pulled forward" reducing the sense of depth.


Repeating shapes


The grasses and the planks in the boardwalk serve as repeating shapes that grow smaller as they recede.
Think of the dashed lines on a highway. Those near you look much longer than those in the distance. Also those in the distance tend to run together while those near you are clearly separated one from the next. There is an illusion that the distance between distant objects appears smaller the further they are away. Apply this idea to photography by using patterns of similar objects, (planks on a wharf, pebbles on a beach) so that the elements of the pattern appear smaller as it recedes into the distance. Our minds interpret this as depth. Once again, a wide angle lens can exaggerate the effect and a telephoto will reduce it.

Converging lines

A strong sense of depth is created by the converging lines.
Photograph a path or a road from the side and it will appear as a horizontal or diagonal line. Do the same from a position in the middle of the path or road and the sides converge imparting a stronger sense of depth that leads you forward into the image. The optical principle here is that parallel lines appear to converge in the distance to a point where they seem to merge: the vanishing point. You can use this principle to impart a sense of depth. Your lens choice matters once again since wide-angle lenses exaggerate convergence. If you include the vanishing point you get a stronger sense of depth; eliminating the vanishing point gives you a weaker sense of depth. So next time you are in a large building, look for converging lines to create a sense of depth. It matters where you stand.

Overlapping shapes


The overlapping shapes as well as the atmospheric perspective imply depth. 
We know that near objects are in front of far objects. Therefore overlapping shapes imply depth. So when you are setting yourself up for a shot and want to create a stronger sense of depth, move around looking for overlapping shapes.

Atmospheric perspective


The depth here is created by the warmer more saturated foreground and the bluer less saturated background.

Dust in the atmosphere can affect the sense of depth in a scene. The further away an object is, the more dust there is between it and you. Hence it will appear lighter, less contrasty and less saturated. This is more noticeable as you look closer towards the sun because all the fine dust is backlit and looks brighter. Telephoto lenses seem to exaggerate the phenomenon. So look for these image planes, overlapping layers in a landscape where the nearest part of the scene appears darker, more saturated and has stronger contrast than the most distant. Also, with increasing distance, objects appear bluer because warm colours like red, orange and yellow are absorbed by the atmosphere. So placing warm hues in the foreground and bluer hues in the background implies depth.

Add them together

The boats serve as objects of known size as well as repeated patterns decreasing in size as they recede. The distant human figure adds another indication of scale.
So even though the camera cannot see in three dimensions like we can, there are tricks to imply depth when creating images. If you use one or more of these techniques together you will create an even stronger sense of depth.



3 comments:

  1. Dennis,

    This is a great visual and verbal summary of how to create depth.

    Thanks,

    Candice Gaukel Andrews

    ReplyDelete
  2. Hi Dennis
    Followed the link from the Adventure Canada newsletter and was very impressed with your examples and explanations.

    Appreciate your effort!

    Peter Campbell

    ReplyDelete
  3. Heya Dennis,

    This is a great explanation; I haven't seen someone pull all the components of depth together in this way before.

    Cheers,

    Allan Tyler Brett

    ReplyDelete