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The ZX-50 (known as the MZ-50 outside of the US) will used any KA mount lens, meaning that they must have an "A" setting on the aperture ring. It will work with older K mounts and screw mounts (with an adapter) but you cannot use the camera's metering with those. I have an MZ-50 (long story, the ending of which is "never buy from Cambridge") which is on long term loan to my sister-in-law and it used all the lenses that I had except for my oldest 50mm.