'All a900 accessories are compatible with the a850 camera,
in November for about $800.'
'The Sony A850's Alpha lens mount is compatible with the full array of Alpha lenses, both screw-drive and electronic autofocus models.'
'All existing accessories for the Alpha A900 will be compatible with the new camera, and sure enough, Sony's photos released today shows the Alpha A850 all cozy with the Alpha vertical grip.'