minolta's first slr, the sr-2, was introduced to the export market in the same year (in fact, at the same philadelphia show as the canon and nikon products) but had been on sale in japan since august 1958. lenses started with the designation 'rokkor'. with the introduction of the srt-101, the lenses added the designation of 'mc' for 'meter-coupled', and then later to 'md' when the minolta xd-11 was introduced with full-program mode.