The effective arrangement of Special Low Dispersion (SLD) and aspherical glass elements has created a lens of compact dimensions. With an overall length of 84.7mm (3.3in.) , it is the smallest lens of this focal range. (* As of April 16th 2004. In the category of wide-angle zoom lens with focal length starting at 24mm and with a maximum aperture of F2.8.) This lens offers a large aperture of F 2.8 over its entire range of focal lengths, which is ideal for low light situations both indoors and out. It has a large depth of field that offers the photographer greater freedom of expression.