Bob's Rikenon lens measurements

[Joel Alpers <rkymtmem@xxxxxxxx>]

(from Bob Clark, who got rejected by the SPAM filter)


Greg lent me his Rikenon lens-testing-jig and I
finally have the measurements of my lenses.  Here
is my raw data and it looks like 4 of my 5 lenses
match very closely.  I'm not sure that I got the
distortion numbers calculated correctly, so I'll
have to go back and re-check them.
-- 
Bob


lens      | G5.1      B1        B2        B3        B4       B5       G5.2
----------|-------------------------------------------------------------------
ser#      | 26372     14774     19777     25621     21856    15784    26372
shutter   | Seikosha  Seikosha  Seikosha  Seikosha  Citizen  Citizen  Seikosha
spacers   | ?         1T+1t     1T+3t     1T+1t     2T       2t       ?
          |
/-diag    | 618       614.5     613.5     614.5     614.5    621.5    619
\-diag    | 619.5     615.5     615       615       615      622.5    621
sum diag  | 1237.5    1230      1228.5    1229.5    1229.5   1244     1240
rel diags | 0.61%     0.00%     0.12%     0.04%     0.04%    1.14%    0.81%
          |
top       | 439.5     436.5     436       436.5     436.5    442      440
bottom    | 439       436.5     435.5     435.5     436      441.5    440
ave horiz | 439.25    436.5     435.75    436       436.25   441.75   440
right     | 437       434       434       433.5     433.5    438.5    437.5
left      | 435.5     433       433       433       433      437.5    436
ave vert  | 436.25    433.5     433.5     433.25    433.25   438      436.75
H+V       | 875.5     870       869.25    869.25    869.5    879.75   876.75
rel H+V   | 0.63%     0.00%     0.09%     0.09%     0.06%    1.12%    0.78%
          |
distortion| 0.11%     0.06%     0.13%     0.03%     0.03%    0.03%    0.01%

Notes:
o The front lensboard of Greg's jig was 760 mm from the wall.
o The image being projected was a 50mmx50mm square, from which the
  corners were marked and measured in millimeters.
o This table is listed in order of lenses tested.
o The light source was a 12V high-intensity lamp.

lens:       G5.1 and G5.2 == Greg's #5 lens (tested twice)
                                B1-B5 == Bob's lenses
spacers:    T == thick; t == thin; I couldn't tell whether there were
                           more than two thicknesses; I left them left on during
                                testing
distortion: the amount the diagonal is longer than you would expect
            from Diag^2=H^2+V^2 (I'm not sure I got this right--it
                                was late)
relative:   the relative measurements are percentage differences from
                                lens B1


Greg's lens data is at:
        http://www.angelfire.com/ca/erker/lenstest.html