Saturday, August 27, 2011

Consistency of RF mechanism

Had been measured and plotted 6 RF mechanisms last week, to verify their consistent performance, thus if they are, we can refer it as a constant, so the only variation of the cam curve is from lens focal performance.

To measure each one, mount the RF part, zeroing it by focus to infinity and make overlay images in window match well, then use this as zero point, focus at other distance, here I choose 8m, 7m, 6, 5, 4m, 3m, 2.4, 2.1m, 1.8m, 1.5, 1.2, 1.0m as target, and record the moving distance of the mirror arm, then plotting the curve representing the records.

Except curve No.4, all six curves has very similar character, indicates the RF mechanism is fairly consistent at their performance on focusing, but there DOES has mechanism like curve No.4, whose character is different, I would call it a "mine", for it is impossible to find out before you bought such a vintage camera produced sixty years ago, actually you could not expect too much. Luckily most people didn't convert 110B as an lens interchanging camera, so they never know.

Nevertheless, most of the RFs are good, but I prefer inspect one by one, before I made the dedicated cam grinding. 

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