Excuse me for being a complete medium format novice here and asking what is no doubt a straight forward base knowledge question, but I am looking to get a medium format camera and have settled on the RB67 or 645 series Mamiyas. But I can't seem to find a comparison of the two anywhere to make things clearer for me. Whilst I'm new to medium format im definitely no novice to photography in general so I would like this camera to be an upgrade from 35mm rather than just an entry level MF. I've been offered a 645 TL For £250, is that a good deal or should I hold out and try to go for a RB67 range, or better value 645 range?? Please help!