Mallincam Xtreme Hot/Warm Pixel Test

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There has been a lot of discussion lately on the Mallincam Yahoo Group about how many hot and warm pixels is normal for a Mallincam.  One contributor (Jon Steel) performed a systematic test, varying camera gain (AGC) and integration time to see what the impact was on the resulting hot/warm pixel count.  I like systematic tests!  Upon seeing Jon's results, I was curious to see how my own Mallincam Xtreme would compare.  Below are the results of my repeating Jon's test.

Settings:

  • sense up 128x

  • ALC off

  • BLC off

  • AGC - off, 2, 4

  • White Balance ATW

  • Gamma 0.45

  • APC - both V & H = 0

  • Noise Detection OFF

  • Lens cap on scope

  • Ambient temperature ~ 20C

  • Dazzle DVC100

  • Brightness 111

  • Contrast 80

  • Hue 61

  • Saturation 60

  • Sharpness 1

Results: (click images to enlarge)

Integration Time AGC = 0 AGC = 2 AGC = 4
2.1 sec
7 sec
14 sec
28 sec
56 sec
120 sec
240 sec

Conclusions:

The one thing that Jon does not mention in his settings is the video capture device he is using, and the capture device settings.  I have tried to match the appearance of Jon's images visually, which required me to have the saturation, contrast, and brightness quite high.  The result is that the number and brightness of hot and warm pixels in my images look pretty much identical to Jon's. 

So, does the number of hot/warm pixels bother me?  No, it doesn't.  The reason is that when I'm using the camera at integration times above 30sec or so, I'd already be at a much lower Brightness, and a Gamma of 1.0.  By 60sec integration my brightness is near 0, and I'd be thinking about switching the DVE darken mode on.  After 2 or 3 minutes of integration, I'd be all out of brightness adjustment, and I'd have gone as far as I could.  Adding filters lengthens the amount of integration time it takes before all the brightness adjustment gets used up since the background is blacker (ie. less light pollution).  The image below is AGC 0 + 240sec integration, but with the brightness = 0, gamma = 1.0, and DVE darken mode on.  Perfectly acceptable.

So, in conclusion, I believe my Xtreme is no different than others out there with regard to the number of hot/warm pixels, but I find that they in no way hinder my observing with the camera.

Cheers!

Jim T.

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Last updated: 19-May-11

 

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