Usually, photographers doing macro work, try to maximize depth of field, not minimizing.
Therefore, most macro photos are shot at f/16, or f/11 on smaller camera sensors, so that as much as possible sharpness can be gained in an image. In club photo judging, the judge usually tells the audience that a macro image up for judgement has too little depth of field, and shooting at f/16 will fix the problem.
I will leave that part of the topic for another day. What I wish to show today, is that a macro lens also has an adjustable aperture. If the maximum f/16 was the only usable aperture, why do macro lenses have f/8, f/5.6, f/4, and f/2.8? I tried this shot just to break the ‘rule’ and I deliberately shot the image at the minimum aperture of f/2.8.
This aperture renders a soft, dreamy background, and only a thin, thin slice of area that is in focus, leading the viewer’s eye right there. [Olympus 60mm macro lens on Panasonic GX1. Hand-held, natural light.]