The most usual means of separation in depth is to place one thing behind another with obvious spacial separation and receding perspective. Near things are larger. |
Unlike our eyes which are mounted side by side ( binocular vision) and give us good depth perception, the camera is monocular, has no natural depth perception, so we must adjust our subject matter to make up for this deficiency. We may do this automatically as we arrange the parts of our 'reality', but using depth of field, useful as it is, is not the only way to go.
There has been a lot of discussion
around this subject. The beautiful bokeh in the blurred background
etc. are an important part of the vocabulary of photographers who use
a large aperture and close subject to achieve a dramatic separation
of frontal subject and softened background. One might think sometimes
that that was the only way to achieve such a separation. But in
practice we use several.
The tree trunk is obviously in front of the cedar branches and is lighter in tone and different in texture and shape. |
In colour and texture there is little separation except for the grey trunk... |
...especially in monochrome. With our eyes we can see the real depth that is present but not in the photograph. The tree trunk adds needed form to this busy image. |
Sharp, red and white rails set off the soft receding background. Allowing the background to soften in the distance supplies a natural sense of depth. Atmospheric perspective. |
In monochrome the close values tend to loose the separation. |
Colour difference gives separation. |
As it does in monochrome as well. Establishing the appropriate sharpness in a snowstorm is the tricky part here. |
Even with all the green we can separate the shape of the lighter tree from background |