|
I've just had a quick glance at the QHY graphs, and it looks like Mode #1 and gain 55 is the closest match to how ZWO has implemented their gain profile.
The QE of the IMX455 is very high, according to QHY. At gain 0, before HGC kicks in, you're getting the full well depth, and full read noise to boot - this may be an option for going long and deep? To be fair, the read noise on existing full frame CCDs is substantially higher, so your SNR will still be better with the QHY600, and this is all with the resolution of 3.75um pixels.
With HGC, it looks like you're sacrificing about half the well depth for roughly half the read noise...hence the dynamic range is comparable.
The dark noise on Sony's latest sensors is quite astonishing when cooled. Even the IMX183 is down to ~0.003.
There is some flexibility with the variable gain on CMOS cameras - personally, I usually stick to 2 or 3 different values, depending on where I am and what I'm imaging and what filter is in front of the sensor.
|