Free Photography Tips for Beginners
Lenses are available in an incredible array of types and focal lengths; from wide angle lens to macro lens to telephoto lens and so on. When choosing a lens it is important to consider the effect the focal length appears to have on perspective. A Telephoto Lens is a specific type of a long-focus lens(85mm to 400mm and longer), it can be used to compress the distance between the foreground and the background of your photograph. A telephoto lens has a narrow angle of view (sometimes as little as 2 degrees). On the other hand a Wide-Angle Lens (15mm to 35mm) can be used to expand apparent distances between objects. A wide angle lens fills your digital sensor with up to 180 degrees of the scene by reducing subject size. Wide angle lens should be avoided for portraiture as they will tend to distort the person's facial features. A Normal (or standard) lens (40mm to 55mm) gives a view closest to what the human eye sees. This can be used for portraiture; however a moderate telephoto lens should give you more pleasing results.
Focal length affects not only image size but also depth of field. A telephoto lens gives a greater image size but a shallower depth of field when compared to a wide angle lens when set at the same aperture. This shallow depth of field is ideal for portraiture when you want to isolate the subject from the background. When using a telephoto lens remember to use a shutter speed 1 focal length faster than the lens or the image will probably be blurred from camera shake .For example if your lens is 120mm, you should use a shutter speed of 250th of a second.