 Further versions, branded Canon 7s and Canon 7s Type II (or Canon 7sZ), modified the design slightly by introducing a cadmium sulfide cell.The Canon 7 came as the first Canon reflex cameras were already on the market, but it was felt that there was a need for a fast-shooting rangefinder camera for reportage.In this niche, the Canon 7 came into direct competition with the Leica M3.