Gain settings

Hello!
What gain and offset settings do you use in your cameras? Are these settings analogous to those in the ASI 2600?

I ran a test in Sharpcap - sensor analysis - and the result showed that the unity gain should be 300.

Every sensor is going to be different. It’s a balance between subject requirements, noise, gain and dynamic range. Don’t worry about unity gain. All that means is that you are using a gain setting where 1 detected photon = 1 ADU of signal. That’s not usually where you’ll find the best balance as described above.

With this camera I use most of the time: Gain=100 and Offset=120.

Regardless of the camera, I recommend using the gain at which your camera switches to the HGC mode, which is when read noise suddenly drops. Going higher rarely brings any significant improvements in the read noise while decreasing the dynamic range, making it pointless in my opinion. Going any lower (or switching to LGC manually if your camera can do that) isn’t worth it either, in my opinion, since when you’re imaging targets bright enough they clip at HGC you can simply take 10-15mins of short subs and combine them after stacking.

For offset, I’ve set mine to 20 and never really noticed any clipping on the low end, but you can go higher if you want, it doesn’t matter all that much.

SkyHoinar · Aug 31, 2025, 10:20 PM
With this camera I use most of the time: Gain=100 and Offset=120.

This is data from SharpCap which shows that the camera switches to HGC at a gain of 300.

📷 omegon.jpg

That’s your sweet spot…

Check what is your RON in ADU instead.

Good suggestions above. I look at the histogram of a dark frame and bias frame under the integration conditions and select the lowest Read Out Noise for gain and an offset with some head room.. Here is an example.

📷 IMX571GainOffset.jpg📷 IMX571MCGainOffset.jpg

This work is part of fielding an 85mm F/2.8 astrograph

https://cdn.astrobin.com/ckeditor-files/14617/2025/7464f91a-23b6-4898-8291-b8d342ce583c.pdf

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