Summary
I was lucky to find some ants that were busy with tasks that did not involve too much movement. When they deal with a dead wasp or building a bridge, the chances to get some sharp pictures are much higher. So, I just kept framing and shooting.
For the moving ants, I had to find a "ant road". I placed the camera and just kept pressing the shutter when the ants passed by. It was pure luck, that I've got some pictures.
The photos in this gallery were taken with an iPhone and macro lens.