Many years ago Hasselblad used to make an accessory called "linear mirror" for calibrating some kind of equipment. I never knew the purpose of this mirror. There was a flea market last week and someone had this accessory. Can someone explain the operation of this mirror ? Thanks. JPAuger.
It is used to make sure the film plane and subject are parallel. As in copping art work or photographs.
Both Linhof and hasselblad sold it. It was made by Zeiss and was the parallel Mirror Alignment Tool. Today you cqan get more universal application ones from ZigAlign. Zig offers both mirror and laser types. The Zeiss one used a curved, front surface mirror. The modern ones use a simpler and less expensive mirror. But the basic Zig mirror system is accurate to 1/5000" which is a tighter tolerance that many can adjust their camera or system to. So the more complex mirror is probably not missed.