3.6 The Effects of Focal Length The choice of focal length is closely related to the camera standpoint, although there are various possible ap- proaches to finding the right combination of the two fac- tors. Some photographers stick to a predetermined cam- era position and select an appropriate focal length, while others prefer to use a particular lens and move about until they find the viewpoint and composition that best match- es it. Using a zoom lens is a more flexible approach, as it al- lows you to adjust focal length steplessly without having to move the camera. If you use a fixed focal length lens, you will have to move around a bit more to find the right position. Extreme focal lengths (less than 16mm or greater than 200mm equivalent) produce extreme effects that are sel- dom useful in an architectural context, but do allow you to capture images that would otherwise be difficult or im- possible to realize. Ideally, every architectural photogra- pher should have access to a broad range of lenses that allow an unrestricted choice of camera position.