Many of the familiar orb-web weaving spiders are in the 'argiope' group, and this species (Argiope trifasciata) is one of the most common.   It is a large, strikingly marked animal -- especially up close -- and frequently sits in the center of its web.   I found these spiders in Palo Alto and near Riverside, both in California.

• (below) Nikon F2, 90mm macro lens with 2X converter, Kodachrome 64 (1977)
• Canon 7D, Sigma 150 mm macro lens, ringflash (2012)