ZWO Camera Settings?

[BlueAstra]

Not sure where the correct place to post this is, so please move if required. I have a ZWO 224c camera imaging through a C9.25. If I use SharpCap 3.2 I get the first image (single frame from video), which appears to be very noisy. If I use FireCapture I get the second image which looks much smoother. I'm pretty sure I used the default settings, more or less, with each software package. Can anyone explain what is happening and how I can get a smoother image in SharpCap? Or is it an illusion and just some display artefact which won't affect the final image?

 

FireCapture Jup_002201.txt SharpCap 00_09_11.CameraSettings.txt

[CraigT82]

It looks like the gain settings in the firecapture image were much lower than in the sharpcap image, also you were only getting 4 fps in the firecapture video. which seems very slow  There is definitely some differences in the default capture settings between the two that would need to be matched before comparing the two softwares.

[vlaiv]

It's not the illusion, SharpCap frame is indeed much much noisier, and there is a reason for it.

If you leave things on "auto / default" software will try to adjust best settings for you, but that does not always work and I would advise against it.

FireCapture used ~9.5ms exposure and 491 gain

SharpCap used 0.32ms exposure and gain 600 (I'm not 100% certain as I don't know exactly what the values are since there is no unit, but I suppose that Exposure=0.000318 should be in seconds and therefore exposure was 0.32ms).

Short exposure is going to produce much worse SNR.

Because I said that you should not use auto / default things, here are few pointers to good settings.

You can choose to use 16 bit (12 bit in reality) or 8bit (10bit in reality) modes. Frame rate will depend on it - 8bit mode is faster to record. If you can achieve wanted fps - go for 16bit. Use SER format and don't debayer your frames during capture (use RAW format to save in - not RGB).

Use high gain settings. If you use 8bit mode, use at least gain of 256 or more (that way you won't get 10bit/8bit clipping). 377 is a good gain setting for both.

Set your exposure time manually. It does not matter if you get histogram to left or right or whatever - as long as it is not clipping to one side. It should not be clipping to the left - offset should take care of that - if it clips to the right, bring exposure down. In general case you want your exposure time to be less than coherence time for atmosphere - it is related to seeing and it represents time in which atmosphere is "frozen" and does not change (so you avoid motion blur although there is distortion of the image). For most part, that time is order of 5-6ms, sometimes you can go longer (10ms) and sometimes you need to go as low as 2-3ms.

Leave everything else turned off - any sort of color balancing, auto exposure, auto brightness, gamma - all those controls need to be "turned off" - or set to neutral.

[BlueAstra]

Thanks for the replies. I’ll try again this evening following the guidelines.