The Watec WAT-120N has three different gamma settings: off, lo, hi. I took series of dark images with each of these settings, to document the effect of this setting.
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The three images show dark-frames taken with the three settings. Each dark-frame is the median of a series of 35 indiviual images with the same settings. |
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The histograms of the dark images show the effect of the gamma setting: The curve is spread towards higher brightness values, with an amplification of low values . |
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Standard deviation of the pixels from the dark-images. For each pixel, the median brightness was established over the range of 35 images. All pixels with the same median-value were combined, to find the standard deviation. Generally, the lower the value, the less noise the system has. The gamma values have a serious impact on the amount of noise, as the images themselves demonstrate. The usefullness of the higher gamma-values appears questionable. |