Find your perfect lens - Shop our wide range of top-quality Sigma Art, Sport and Contemporary zoom lensZOOM LENSAllows a camera to, unlike a fixed-focal length or prime lens, change smoothly from a long shot to a close-up or vice versa by varying the focal length. A true zoom lens, also called a parfocal lens, is one that maintains focus when its focal length changes. Due to more moving parts, zoom lenses often produce images of slightly lesser quality than their prime lens counterparts. However due to the inherent flexibility of being able to vary the focal length, they are extremely popular for photography where composition needs to be adapted quickly - such as at weddings, for example.es for Canon and Nikon cameras. Contact us for expert advice as to which lens will suit your specific needs.