SharpCap Forums

Hi Robin,
In the process of getting some help on my calibration frames on the Cloudy Nights forum, someone pointed out that the internal white balance settings saved inside my camera (ZWO asi 2600MC) are incorrect, and as a result my dark frames have a strong color tint (and should not). The person helping me said I should change the internal camera settings to 50 for white balance using ZWO's asi studio software. But he wasn't familiar with Sharpcap enough to know if it can over-ride the camera's settings. So... do the Sharpcap white balance sliders (for blue and red) over-ride the camera's internal settings? And if so, should I change the camera's internal settings, or leave them alone?

Here is what he said:

"There is a pretty significant issue with the data coming from the camera. It seems that the internal white balance settings saved inside the camera are incorrect. This becomes immediately obvious when you deBayer a Dark frame. They have a strong color tint. Since a Dark frame never sees light, there should not be any obvious or strong color tint present. (The camera is modifying the data before it is sent to the capture software. You do not want that to be happening.)

For future imaging, you should correct this so that you are processing unadulterated data. Once corrected, they should be good for all future sessions since they are saved inside the camera itself. (I'll describe how to set these correctly at the bottom of this post.)"

Hi,

I'm not aware of any internal white balance settings for ZWO cameras that have to be set in ASI Studio - as far as I am aware, the white balance settings that you see in SharpCap *are* the white balance settings for ZWO cameras.

The 'neutral' settings for ZWO are to set both values at 50 - this is what I personally would recommend. ZWO themselves default the settings to different values (like 90 for the blue and 55 for red or something). The ZWO default settings give a reasonable looking daylight image rather than the yellow/green cast of the neutral 50/50 settings. I suspect they do that so that the colour of a first test image looks OK when the camera is first used out of the box, as they will get less support requests about odd colours that way.

So, anyway, I would suggest using settings of 50/50 at all times for all ZWO cameras to get the true raw values from the camera. This should be for all types of frame (dark, light, flat, dark flat, bias, etc). That gives you the raw unprocessed data from the camera sensor. On the other hand, you can get good results using non neutral values for the white balance, but again make sure you use the same values throughout in all the different types of frame.

No need to set these values anywhere else - just adjust the sliders in SharpCap as required.

cheers,

Robin

Ok, thanks. I’ll set the white balance controls to 50/50 in Sharpcap for lights and all calibration frames.

Hi Robin,

I have one question on this. With the white balance controls for R and B both set to 50 in Sharpcap then when you look at the histogram - naturally - the green signal is well over to the right compared to the other two.

So when trying to use the histogram to set the exposure the setting should be based purely upon the green response in order to prevent overexposure ? - or should the channels first be auto-balanced so that all 3 channels coincide ? I have sort of assumed that it doesn't matter but maybe it does?

thanks
Tim