The AE-1 was the vanguard of the landmark Canon amateur level A-series SLRs and led Canon's charge into the emerging electronically controlled SLR market. The other members of the A-series were the AT-1 (released 1977), A-1 (1978), AV-1 (1979), AE-1 Program (1981) and AL-1 (1982). They all used the same compact aluminum alloy chassis, but with different feature levels and outer cosmetic plastic top panel. By sharing most major components, including an inexpensive horizontal cloth-curtain shutter, viewfinder information display, and autoflash control, Canon further reduced costs and could undercut the price of the more expensive SLRs then on the market.