Focus parameter changes due to new camera

I am using an earlier version 2.X of SGP and I switched to a camera with a much bigger sensor. Parameters that gave a beautiful focus parabola with a few dozen stars is now choking on seeing hundreds of stars at focus and results in distorted focus curves. Looking for guidance as to which parameters would likely be changed and how, in order to get back to a better curve.


You will likely want to change the step size as the size of the pixel as well as the critical focus zone has also changed. It’s probably worth going through the setup process of finding best focus (manually) then moving until the HFR is 3x your best focus…and then plugging in the numbers:

StepSize = 2 * (3xHFRFocusPos - BestFocusPos ) / (AutoFocusDataPoints- 1)

Best position = 900 steps
3xHFRPosition = 1300 steps
AutoFocusDataPoints = 7

2 * (1300 - 900) / (7 - 1) = 133.333333
So Step Size of 133 in SGP.


Thanks Jared. Appreciate the info. Now for a clear night…