It seems that the strength of the SCA system largely disappeared about the time of the dSLR and their xTTL flash exposure systems. While my 54MZ units could be made to work with different dTTL systems via the appropriate SCA module, Metz seemed to have abandoned that approach with their nnAF line of flash, dedicated to specific brands. I have a 64AF-1 for use with Canon digital camera flash automation, athough I have 4 other Metz flash units of hammerhead or on-camera speedlight design, all of whick I can use with the multiple brands and formats of film cameras (and digital, in the case of the 54MZ) I have no insight about why Metz changed its approach to offering 'dedicated for XYZ' flash units, as opposed to continuing with SCA-adaptable flash units.