The other important setting on your camera for still life is depth-of- field. This is the area of the subject that appears in focus.
The lens can only focus on a single image plane, so only the part of the subject you focus on will be in sharp focus. However, an area in front of the focus plane, and an area behind the focus plane, will only be slightly out-of-focus. They will appear to be sharp to the human eye. This area of apparent focus is called the depth-of-field and changes as you alter the aperture. Small apertures, such as f/16 or f/22 give the greatest depth-of-field; wide apertures, such as f/2.8 and f/4, give a narrower depth-of-field.
My first laptop, © H. J. Epskamp 2010, Canon EOS 50D
Another factor affecting depth-of-field is the distance between the lens and the subject. As you focus closer, moving the camera nearer the subject, the depth-of-field will be reduced. Typically still life photography is done with the camera relatively close to the subject. This means that the depth-of-field will be limited so only a small area in front of and behind the point of focus will appear sharp.
You can use limited depth-of-field to good effect. If you are photographing three chess pieces, for example, in a composition which places each at a slightly different distance from the camera, focusing on one piece will throw the other two out of focus. You can change the image by focusing on a different piece.