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Rikenon Lens Test Data and Results

I used my jig and projected a test slide on the wall from a fixed distance with each of my five lenses. I marked (and then later measured) the the four corner points of a 50x50mm square and the vertical and horizontal distances across the edges of the square.

Lens No. Serial No. Condition Diag.1/Diag.2 Sum Diags Horiz./Vert. Sum H+V Relative FLs (diag) Relative FLs (h+v) Distortion*
1 35915 EX, f3.2 viewer 619.0/618.0 mm 1237.0 436.5/433.0 869.5 Reference lens (0.0%) Reference lens (0.0%) 0.60%
2 29432 EX, f3.2 viewer 622.0/621.5 mm 1243.5 438.0/434.5 872.5 0.53% 0.34% 0.78%
3 21316 EX, f3.5 viewer 621.5/620.0 mm 1241.5 437.5/435.5 873.0 0.36% 0.23% 0.56%
4 14469 rear element separation 626.0/625.0 mm 1251.0 440.5/438.0 878.5 1.13% 0.92% 0.69%
5 26372 front coating scratched 620.5/619.5 mm 1240.0 not avail./435.5 435.5 (V only) 0.24% 0.58% (based on Vert. only) 0.67% (based on Vert. only)

* Distortion is the amount the diagonal is longer than you would expect from Diag^2 = H^2 + V^2.

Marking and measuring the distances is probably accurate to with 1mm (+/- 0.5 mm). Thus diagonal measurements are accurate to 0.08% and comparisons between diagonals are accurate to 0.2% or so. Thus I am fairly confident that the top 3 lenses are close matches. The measurements of both diagonals and the horizontal and verticals increases the confidence since they agree to with the 0.2% error.

The distortion measurments are most error-prone since you are basically subtracting two measurements. Thus their error rate is likely higher.

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