Some people suggested that auto-focus was slow and not so reliable for macro photography. That was not entirely correct. If you understand auto-focus well, you will know when to use and when not to use it. Auto-focus provides excellent assistance in the field.
Canon and Nikon DSLR
When paired with the right lens, the phase detection auto focus systems in Canon and Nikon DSLR are generally reliable for macro photography. Basically, their mid-level DSLR can be configured to use the following combination.
AF-On/Continuous Focus and Disable Half-press AF
The configuration disables half-press AF. If you do not disable half press AF, the AF system will try to hunt for the target every time when you half press the shutter button. By default, manual focus will be used.
To use AF, you may simply press AF-On. Together with Continuous Focus mode, you can enable or disable auto focus in a very flexible manner.
Sony DSLR/Translucent Mirror Camera (A7/A77 or higher grade)
Sony DSLR and Translucent Mirror camera have similar phase detection AF system like the Canon and Nikon DSLR. However, the difference in the buttons and interface configuration do not allow users to configure the camera in the same way.
Continuous Focus with AF/MF switch
Most Sony camera do have carry AF-On button or the behavior differs from Canon and Nikon. However, there is usually a handy AF/MF button that you can configure it to switch between AF and MF.
Mirrorless and Other Contrast AF Based Camera
Earlier mirrorless models are not reliable for any handheld macro photography. The liveview delay and the shutter lag make these earlier models not suitable for the task at all.
More recent model like Olympus EM5 and EM1 are reasonably reliable in single focus mode. “Bridge camera” like Sony RX10 is also a reasonable performer here. While their continuous focus modes may not match Canon/Nikon DSLR in macro photography, single focus AF mode is quite usable.