It also depends on the lens - most macro lenses that do greater than 1:1 don't even have auto focus so it does't apply. The problem comes in when you are at greater than 1:1 and the dof gets so thin that the af has difficulty or cannot properly focus on the area of interest of your subject, such as the critters eyes. I only hand hold and use manual rack focusing myself, even with my ef 100mm lens. but you have to actually play around and see what works for you. As for YouTube macro tutorials, you have to do some good filtering to get decent ones that aren't rubbish. And from my pov macro is only 1:1 or greater, so even the canon lenses that say macro but are only .5x / .5:1 are not considered true macro lenses, they fall into the close up photography category which is acceptable and legitimate, but not true macro.