Hi all, I stumbled upon this blog post regarding converting a 220 film back to a 120 film back (or vice versa): Convert Pentax 645 645n 645nii 220 film back to 120 film back – Pentax 645 Tl;dr: there's a simple plastic part inside held on by a small screw. Flip the piece 180 degrees, and it changes the type of film the back accommodates. Can any of you 645 shooters attest to validity of this modification? Is it really just that simple as reversing one simple internal part? Usually when something seems to good to be true, it usually is. Thanks!