As described in Chapter 6, the skeleton is divided into axial and appendicular portions (see Figures 6.1 and 7.1). The axial skeleton is structured from 80 bones segregated intothree major regions: the skull, vertebral column, and thoraciccage (Figure 7.1) . This part of the skeleton (1) forms the lon-gitudinal axis of the body, (2) supports the head, neck, and Chapter 7 The Skeleton 199 7 Figure 7.1 The human skeleton.
Above: Some cameras have a switch to set it to auto or manual focus. Manual focus, meanwhile, disables autofocus and enables you to adjust it yourself. This is useful when the focusing system can't find focus for whatever reason, such as when it's too dark or when there's little contrast in the scene.
For instance, Canon uses the front dial to adjust shutter speed and the back for aperture, while Nikon uses the reverse. Lower-end cameras generally have just one dial and point-and-shoots sometimes use the navigation buttons. You might need to check your manual to figure out how to adjust one or both settings.hile in anything other than full auto mode you can control all a camera's settings, but only Manual mode lets you adjust aperture and shutter speed independently. For more information about other cameras modes, check out what all those camera modes are for, anyway.