I would thing the smartest way is just to detail my question, then follow with my qualification level afterward. I hope some Hasselblad-qualified people dive in, just for my edification, as I have no intention to take their knowledge and then compete with them by hanging a camera-repair shingle. So on with the question: why is there seemingly no point of perfect infinity when I switch lenses across the old 500CM's and ELM-era cameras? I've worked on maybe 20-30 different Hasselblad items. Heck, maybe 50 times by now... I clean and re-lube the lenses or foam the bodies--stuff like that. And you know something truthful?--there's never any meaningful infinity adjustment. Take the 80mm off one and put it on another, and it's never dead-on. Sometimes a downright disappointment. Or maybe I'm just too sensitive. Now that my question is stated, please give due credit to my 45 years of working on cameras as an extremely advanced hobbiest. I know that the Hasselblad repair people have gazillions of dollars of equipment and tolerances to the electron. I know full well what I have no business taking apart or fouling up, without the right test fixtures. Thank you.