Hi Gents,
Loong time no post, and fitting to post in a thread thats so old
I've just returned to setting up my system again, and in an attempt to ensure everything is setup correctly and optimized I was hoping you could check my calcs on autofocus..
I havent had any issues as yet with focusmax with 4 microsteps; but without crunching all the numbers just yet; just checking Im understanding this correctly.
I havent as yet measured the exact draw tube distance and counts to work out the step/microns, so Im assuming what others reported on yahoo forums to be similar.
Going by the previous mentions of steps to microsteps; and ensuring the focusroutine(FcsMax) is running correctly; I believe as Jase mentioned for the FSQ at 3 microsteps or even two gives a +- 3 counts for focusing in the CFZ and accounting for change; though focuxmax magic can mean measure the best HFD anyway as long as the counts(steps/micron) dont overlap the CFZ.
Not sure how critical checking this against diff filter(nm), but will work out after for the satisfaction of knowing nayway..
*gulp, my workings below.
So 3 or 4 microsteps should be fine; 2 may be a waste of time(pun).
4000 steps Focuser draw tube distance
using 1:1 step /microstep
------------------------------
55micron CFZ
Tak106
reported as: 6.7microns/step
55 micron / 6.7 micron = approx. 8 steps(counts in CFZ).
2 microsteps x 6.7 = 13.4 micron 55/13.4 = 4.1(4) tolerance steps(count)
3 ...steps x 6.7 = 20.1 micron 55/20.1 = 2.73(3)
4 ...steps x 6.7 = 26.8 micron 55/26.8 = 2.05(2) <--- +- half 1/2 CFZ
5 ...steps x 6.7 = 33.5 micron 55/33.5 = 1.64(1-2) <--- +- almost 2/3 CFZ