Saturday, June 18, 2011

Rangefinder calibrations on 110B- part2

Here are three main factors that you should know before you made a cam to fit to a lens.
1. Lens: You should know the range that lens can move on the rail, it is fixed range on 110B. But most important factor is within the moving range, how will the lens focus change?
Take 150mm lens as example, within the 110B rail moving range, it can focus between infinity to about 1.5m; in the same moving range, a 90mm lens can focus as near as 0.6m.

2. cam: cam curve controls the rotating range of the mirror, but cam rotates itself as rail moves, you should find out the cam rotation related to rail moving range.

3. RF mirror: All RF parts are fixed except mirror, it moves to change the RF focal point, I have shown you that for a 127mm lens, all the mirror moving range needed is within 1mm, but how about 150mm lens? how about 90mm lens?
Rail moving range is fixed, thus made 150mm lens to 1.5m, 127mm lens to 1.05m, 90mm lens to 0.6m. So we know that 1mm moving range for 127mm lens, and that will cover 150mm lens as well, but not enough for 90mm lens, we should extend beyond 1mm to reach the 0.6m focal point, it needs extended measures.
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