Compisitions and Zooms

Zoom Lenses allow you to change the magnification of an image without swapping lenses. Zooms are designed to change the field of view of the lens while keeping the image in focus. When the field of view is widened (to take in more of the subject), the image must be reduced in order to the sensor of film area. This is the effect of using a short focal length lens or a wide-angle setting on a zoom. Conversely, when the field of view is narrowed (to take in less of the subject), The image must be magnified again in order to fill the sensor or the film area. This is the effect of using a long focal length lens or a zoom's telephoto setting.