Wednesday, June 15, 2011

Rangefinder calibrations on 110B- part1

There is a mirror on rotation, according to the cam curves, thus each cam for different lens, will have different curve, reflecting the focal length.

this is cam for 127mm lens,
Vertical line on cam surface indicates when lens is focus on infinity. and as rotating in hole center, each degree of outer curve on top is keeping changing the radius distance, causing mirror rotate.

But how long the radius range a cam causes?

I used a usb micro scope to take photo of cam, and enlarged it, then make some distance measures.

After carefully measuring, converting digits into a curve, we found that outer curve of 127mm cam actually causes mirror rotate within 1mm range.

That means a lot, range finder that 110B equipped, focus from infinity to near 3.5feet, all controlled within 1mm range.


Bob Crowley said...

1mm is not much is it? But, it is enough. I wonder about a two-level cam, one for the 90mm lens on my favorite camera?

Salihonba said...

I am dreaming of a three levels structure.