Nikon D50 Repair Manual page 90

8. Summary
The summary on each adjustment is as follows:
(1) Sensitivity adjustment
Face the camera to the color viewer of LV13 equiv. putting the ND filter (-5 step) between them, and make
an adjustment by changing the ampgain so that G output can fall in the standard range. Adjust the gain
value so that the G output average value (Average of Gr/Gb) in the center (300×300 pixels) can reach the
target output level (approx. 600LSB). The actual adjustment of the gain value is made only under the
condition of ISO200 and ISO1600, and the medium sensitivity is calculated by the adjustment values of
these 2 conditions.
For target output level, use the G output average of sensitivity reference value (ISO200) that was calculated
by the reference body.
Gr/Gb compensation adjustment (R/B filter)
(2)
Face the camera to the light-emitting box (color viewer) of LV13 equiv. putting the SP3 (R filter)/SP1 (B
filter) between them, and make an adjustment so that the output difference in G output average between
G-B line and G-R line when the whole screen is divided into areas can fall in the standard range.
(3) Sensitivity ratio adjustment
Face the camera to the color viewer of LV13 equiv., and make an adjustment so that the R/G, B/G output
becomes the same as the output ratio of the sensitivity ratio reference value that was calculated by the
reference body. Adjust only under the condition of ISO200, and use the average value of the center (300
pixels × 300 pixels).
(4) Gr/Gb compensation inspection (No filter)
None
(5) CCD black point defect compensation
When pixels of which the output level is under specified value with LV13 equiv., are detected, rewrite the
coordinates of the detected pixels as pixel defect compensation data.
(6) CCD white point defect compensation
Take a shot on the dark surface. In case the pixel output is found to be beyond the standard value, store the
detected pixel coordinate as the pixel defect compensation data.
(7) "Sensitivity" and "Sensitivity ratio" reference values calculation
・Sensitivity reference value calculation
By using the reference body, face the camera to the color viewer of LV13 equiv. putting the ND filter (-5
step) between them. Then, store the G output average value of the center (300 pixels × 300 pixels) in
the STD.DAT file as the sensitivity reference value.
・Sensitivity ratio reference value calculation
By using the reference body, face the camera to the color viewer of LV 13 equiv. (without filter). Then,
calculate the sensitivity ratio reference value GR and GB based on the G/R/B output average of the
center (300 pixels × 300 pixels), and store them in the STD.DAT file.
It is necessary to calculate the reference values of "Sensitivity" and "Sensitivity ratio" in order to prevent
the color temperature fluctuation caused by color viewer's changes over time from affecting the results of
the shooting image adjustment. By using the reference body, calculate the reference values once in about
every 3 months, when the fluorescent of the color viewer is replaced.
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VBA12001-R.3668.A