I have put this together to be used to calibrate the microfocus on DSLR cameras - still to print and test, this should be treated as an untested prototype
Cura is showing that this will take 52 hours and 38 meters of filament to print at .05mm layer height
or 26 hours at .1mm layer height
if you scale it to 50%, then it will take 11 hours and 7m of filament at .05mm layer height - it should still work - provided the lines are clear enough for the camera to focus on
I would recommend printing in white and painting the lines in black (or vice versa), to allow for easier focusing.
I printed this myself at both 50% and 100% scale - sadly my printer does no have the accuracy to print the calibration lines. as a result, I have edited and provided a v2 file where the calibration lines are 1mm thick, this should print a bit better on models with lower accuracy - I am testing now at 50% scale, results will be posted later.
print at the highest resolution you can - as the lines are designed to be .1mm thick, as the calibration is for very fine focus