Reason for asking, is that because Contax 645 prices (of which I have a huge system) keep rising and because H-system lenses have the same compatibility with Leica S (007), I seriously consider to replace my C645 system for a brand new H5D-200ms-c... But I plan to keep my Imacon 528c back as well, so it must be usable with the system I will choose (if it will be an H system)... My intension is to shrink my system as much as possible, while improving task ability at the same time... I plan to replace my Nikon DSLR system with a Leica S (007) and use MF system lenses on the Leica (either H645 or C645)... But a modern MS back is essential too... The back, will either be H-200MS or Sinarback e-Xact... If it will be the Sinarback, the MF system will remain the C-645 as is... 200ms-c will be considered depending on the answers posted on the O/P questions...