I suspect you are dealing with larger objects. I was trying to take photos fully zoomed out and getting too close as the objects were v small. If the objects are not too close for the camera, then it would presumably be better to keep it zoomed out and get up close (that way you get less camera shake and max depth of field). If the objects are too small for that, then back off to the minimum distance and zoom.
I hope that makes sense - it is late !
Cheshire Steve