Nick,
A couple of things come to mind if you are not getting HFR low enough:
-Double check your sampling. If you are far less than one this could cause bloating. If you have a mono cam try binning 2X2 or 3X3 and see if the HFR changes.
-Try an object or area where no large stars are present. A bright star can alter the average HFR for the whole image and affect your V-curve.??
-With the ZWO EAF (what you have?) I have never found auto-focus to work that well (in SGPro) and the V-curves are pretty bumpy. My MoonLite CHL produces very symmetrical curves all the time. With the ZWO I usually just try to move in and out with the position controls and check the HFR number after each click and check where the lowest HFR is.
All the best,
John?
