Proper gain setting when livestacking - ZWO asi 2600MC camera

[Moonstruck]

Robin,
When I am livestacking using the ZWO asi 2600MC camera, what gain setting should I use? The unity gain (as you know) is 100 for this camera, but should I increase it when livestacking? I am asking because I have seen a lot of on-line videos showing the gain set at very high levels (say, at or over 300).

Also- does the gain setting affect how the finished (post-processed) images will come out? I like to get a nice bright image on the screen when live stacking, but also want good final images.

[admin]

Hi,

I think I would recommend a gain somewhere from 100 to 200 for this camera - getting the gain to 100 or above gets you on the lower side of the big step change in read noise that you can see in the read noise graph on the camera product page. However, increasing gain beyond that doesn't really do much for further read noise reduction (at least not until you get to exceptionally high gain), so all you are doing with higher gains beyond is brightening the image, and you can do that with stretching anyway.

Unity gain is actually about gain -15 on this camera - it doesn't exist at all in the normal operating range of 0 gain upwards, only in the 'high full well depth' mode with negative gain. Don't worry about unity gain - my opinion is that it's not really a massively useful thing.

The gain does affect the brightness of the input images, but since you can stretch your image as you like in live stacking, you can compensate completely for any lower input brightness with the stretch.

cheers,

Robin

[Moonstruck]

Thanks. I have been using a high gain while livestacking (over 300- as I saw in various video tutorials on line), but will try a lower gain next time, and stretch the curve more instead to increase brightness.