Understanding Focal Length

Focal Length: 18 mm

Focal Length: 24 mm

Focal Length: 35 mm

Focal Length: 55 mm

Different lenses have different types of zoom.  A Prime lens has a fixed focal length and it is smaller and more light weight.  However, a zoom lens has variable focal lengths, so you do not have to change to lens as frequently because you can change your focal length.  The smaller the focal length, the farther away the object appears.  The larger the focal length, the closer the object appears.