>  The 50mm Cintar on the 21 looks pretty similar to
                                    the C3's lens, though I
                                    >  notice that Argus once again made sure that there was not one shred of
                                    >  interchangeability between their various cameras.  Were there ever the
                                    >  equivalent of the Sandmars available for the 21?  
                                    >  
                                    >  I notice that the 21's lens thread is tantilizingly close to a Leica
                                    >  screwmount thread, but just a little bit smaller in diameter.  
                                    >  
                                    >  Carl Turner
                                    
                                    
                                    The 21 with interchangeable (not just removable) lenses would have
                                    been quite a nice little camera (shutter tensioning not withstanding).
                                    This might be a nice home-brew modification for someone with the skills
                                    (reminicent of the "Mystery A" on the web site).
                                    
                                    Mike Reitsma
                                    

Some rough measurements (very rough!  Don't cut the metal
                                    yet!)  show that the
                                    21 has a flange distance (flange to film rail plane) of about 38.4mm.  The C3
                                    has a flange distance which is greater at 41.9mm.  Also the C3 has a lens
                                    mount diameter around 32mm as opposed to the 21's 38mm diameter.  Therefore,
                                    it would seem possible to turn an adaptor that would thread into the 21 that
                                    would then allow the C3's Sandmars to mount and space them out at the C3's
                                    greater flange distance.  The Sandmars of course have their own distance
                                    scales so can be scale focused just fine.  
                                    
                                    Now that would be something to brag about!  I'll add this to the list of
                                    things I should make if I weren't so lazy.  
                                    
                                    Regards,
                                    
                                    Carl