I agree that being able to raise the gain to 300 is definitely an improvement over putting the limit at 100. However, the camera is able to support gains above 300 and especially when using narrowband filters and imaging faint objects under dark skies, it can be quite tempting to want to use gains up to 500 or even 600. I've made some measurements and at least for my sample of the 2600MM, it seems that the read noise drops to 0.8e- at gain 500. That's significantly below the 1.15e- I get at gain 300 (I've measured 3.3e- at gain 0, so the measurements seem valid). I think the defaults for low (0), medium (100) and high (300) definitely make sense in Asiair. However, I don't see why you shouldn't be able to pull the slider up to 600. There are objects (one of which I'm currently imaging) where on average only 1-2 photons hit a pixel every minute, so having a full well of only 50e- (at gain 600) isn't a big deal even when taking 10 minute exposures. After all, that's exactly how the gain setting works for my ASI290MM Mini. I also don't think the ASI2600MM as a mono camera can be categorized as a "beginner" camera. As much as I appreciate your focus on beginners, locking more advanced users out of a feature of a quite expensive camera in a way that wouldn't actually complicate anything for beginners seems rather absurd. I really hope you'll make it possible to use the full gain setting range in a future release.