1.00   2.796   7322.5
1.25   2.405   7795.8
1.50   2.339   8479.8
1.75   2.647   8473.9
0.50   4.009   3733.8
0.75   3.058   7225.4
best focus is 1.38939  (max peek at 1.49405)
focus done f=1.38