Dahua Color 4KT Optiimizing for Star Field

[guykuo]

Did some experiments with varying shutter times from 200 to 1000 msec. The longer times are possible using CGI commands, but counterintuitively, the camera actually gets better star captures with shortish exposures rather than super long. On mine 225 msec with a gain of 50 gave the most stars with least white pixel noise. Gain has to be carefully adjusted to match the shutter speed. Just a single click too high on gain introduces white pixel noise into black areas.

Here is a segment with those settings. I did push the gamma to be non-linear during editing, but you can see how clean the capture is of white pixel noise.
I can see planes, satellites, and at least one meteor in this clip. Lots of stars - better than I was getting at 250 or 333.33 msec shutter. Sped up 90 X.
View attachment Star Field Opt.mp4

 

[Ri22o]

I have it on my to-do list to mess with mine and see if I can get better images. I am dealing with some light pollution though which is making some angles difficult.

 

[guykuo]

Some useful CGI commands for adjusting night profile gain and shutter speed. FPS in encode should already be set to match slowest frame rate that goes with shutter speed.
Camera will drop frame rate if exposure time exceeds that possible at current FPS.

The 1 in second parameter in [0][1] means do setting in night profile
Assumes profile is in manual mode.

Gain night, GainMax is active gain setting
http://nnn.nnn.nnn.nnn/cgi-bin/configManager.cgi?action=setConfig&VideoInExposure[0][1].GainMax=50

Shutter night, msec is Value2
http://nnn.nnn.nnn.nnn/cgi-bin/configManager.cgi?action=setConfig&VideoInExposure[0][1].Value2=225