The 1970s and 1980s were an era of intense competition between the major SLR brands: Nikon, Canon, Minolta, Pentax and Olympus. Between circa 1975 to 1985, there was a dramatic shift away from heavy all-metal manual mechanical camera bodies to much more compact bodies with integrated circuit (IC) electronic automation. In addition, because of rapid advances in electronics, the brands continually leap frogged each other with models having new or more automatic features. The industry was trying to expand out from the saturated high-end professional market and appeal to the large mass of low-end amateur photographers itching to move up from compact automatic leaf-shutter rangefinder (RF) cameras to the more versatile SLR but were intimidated by the need to learn all details of its operation.