 They experimented with an external rangefinder mechanism with a turning prism as used in Zeiss Ikon Super Ikontas, but as the production shifted to Singapore this idea was abandoned.Following the preproduction run of 50 pieces, 200 cameras were made for use as advertising and testing samples.After 900 pieces of the regular models had been built by the end of 1966, in 1967 each month 1000 cameras were produced.