The 1970s and 1980s were an era of intense competition between the major SLR brands: Pentax, Nikon, Canon, Minolta 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 camera bodies modularly built with substantial amounts of lightweight plastics. In addition, because of rapid advances in electronics, the brands continually leap frogged each other with models having new or more automatic features. The introduction of integrated circuit (IC) microprocessors made it easy for SLRs to provide convenience features like electronically timed shutters, electronic autoexposure, electronic information displays (using LEDs or LCDs) and use electronic computer calculated zoom lenses. The industry was trying to expand out from the saturated high-end professional and advanced amateur 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 and glamorous SLR but were intimidated by the need to learn all the gritty details of operating a traditional SLR.