With macro, especially extreme macros like 1:1 has challenges. Not only it is difficult to get enough light in to properly illuminate the subject and keep the shutter speed high (otherwise motion blur will ocurr), but also keeping the distance from the subject steady is hard. Please note, at this kind of distance and with reasonable aperture that will enable you to hand-hold, your DOF may be tenth of an inch or narrower. If you move forward and back even JUST a little, you can easily move outside of DOF resulting in soft image.
I have 105mm f/2.8 macro. Handholding is a challenge.