Slider rail

Macro slider rail
For mounting on a tripod, and gaining supreme control of how your camera is situated in front of the object, is the slider rail, which means that you can move your camera about 5 cm in each of four ways, (10 cm in two ways), for fine adjusting the placement of the camera. This way you won't have to move the whole tripod setup. Just by the turn of some finger screws you can move your camera. This is very useful if you want to do focus stacking for example.
I also see this useful in tabletop studio setups, where you may have a still life set up and will just need fine adjustments.
You can find a slider rail at Amazon.