HI @klarkamatej. I am an amature photographer.
To be for specific if i use f/8 to f13. depending on the distance of the subject. the DOF will be small or narrow. that's why sometime it only focus on eye or head. then lately i found out. i can use f16 to f/22 above. by using slower shutter speed like 1/60s and using the external flash +3EV. i shoot handheld so that i can move freely. in macro shooting the camera, photographer and subject movement can cause blur. btw i also use ISO 100 only on macro as much as possible so i can crop he photo if needed. Hope this answer your question.