Focusing Vcurve

When I focus, I have my setting to give me a full V curve, about 13 steps, is it necessary to complete a full curve or will SGPro work just as well if I reduce the number of steps?


The autofocus should work fine if you reduce the number of steps, though I wouldn’t go below 7. I have mine set to 9 steps, and you should aim for an out of focus HFR that is 3x what your in focus HFR is. For example, if your HFR value is 1 when in focus, adjust your step size and number of steps so that the outer two points of the V are around 3.

9 is about right. Since your current method is producing a V, I would use:

13 * current step size = 9 * new step size

Thanks for the replies, I feel that my step size is o.k, I get about 3 steps covering the cfz of 55 microns, so I will reduce the number of steps to 9.
I expect that I will see more of a tick shape, rarther than a full V, but it should just quicken the process which is really what I want.

Ta Ray

You should see a full V, at least if you are fairly close to focus to start, the points will just have more physical focuser steps between each point…

My practice has always been to do a manually triggered autofocus before I start the sequence but after I am on the target and just “run again” if it is too far off center. This helps to insure that things get off to a good start and only takes another 3-5 minutes and wastes little imaging time as it can be done before full dark.

Personally, I use 11 steps. I do not mind a bit more time since the extra time is trivial in any case.

I guess that’s a fair point it certainly feels correct to have the full V, and I guess a minute here or there is pretty irrelevant!
I expect the reduction in step # would show as the focus moves away from the cfz, I will also experiment with my step size but 3 steps around the cfz feels about right.