The all important apparent difference in perspective exhibited by wide-angle and telephoto lenses comes about because of the change in reproduction ratio or magnification. A subject which fills the viewfinder when using a telephoto lens must be approached must more closely to capture a similar image with a wide-angle lens. The two views therefore appear subtly different and the apparent relative positions of objects with an image may change. A telephoto lens has the effect of compressing distances, making background detail appear closer to a foreground subject than was actually the case. Wide-angle lenses have the opposite effect, and tend to exaggerate distances between objects. Standard lenses are designed to produce a field of view and perspective close to those of the human eye. However, bear in mind that perceived differences do not actually exist in a strict optical sense, as all lenses obey the same basic rules. The telephoto view of a subject can be cut from the centre of a wide-angle view taken from the same location. It is the change of viewpoint that makes all the difference.