Choosing the right lens is an important part of getting the results you want. The two most important things to consider are ‘Focal Length’, and ‘Depth of Field’. 18mm (and lower) have the widest focal lengths and are considered wide angle lenses. Wide angle lenses are great for landscapes and interiors because you can fit a lot into your shot. A 200mm lens would be considered a telephoto lens, and they’re great for zooming into shots that may be further away.