I received feedback from Raymond who told me that "the focus scale, the ground glass and the rangefinder did not agree on the focus distance." That brings me curiosity how precise the RF on 110B? I never doubt about the distance scale that camera shows me, until this time.
So I managed to measure the REAL distance scale that read out from ground glass panel. After some cameras were measured, a curve plotted to represent the relationship of focus distance and the rail movement.
Black curve represents the measure I made from ground glass, the blue curve is what distance scale on camera marked.
The curve tells me some facts that I should let all of the polaroid 110A/B owners to know, that is "the distance scale on camera is IN-CORRECT"!!
How surprise! I did trust the credits of Polaroid, their reputations of the quality control on productions......., but I should check before that!!
The curve tells me that 127mm lens actually can not focus as close as 3 feet, like the distance scale shows, 3.6ft (110cm) is the nearest distance that camera can focus.
And the curve tells me more, that the distance scale is somewhat correct from infinity to about 5 feet, and then incorrect increase when focus closer.
Scale in purple is what real distance scale should be, according to my curve. You can notice that distance less than 5 feet(1.5m), the curves significantly differ, and when the rail extends to the end, it actually focus at about 3.6 feet, not 3 feet.
I should re-mark the distance scale on Byron