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 leapfrogged each other with models that had new or more automatic features. SLR camera manufacturers were attempting to expand from the high-end professional and semi-professional market to the growing consumer market. The latter desired an affordable, yet full-featured 35 mm camera, but were intimidated by the need to learn the intricacies of operating a traditional SLR.