to help keep it sharp, as well as using a tripod and the cable release you should have the mirror set to lift on the first press of the shutter button and then take the picture on the second press. This is quite easy to set up and on macro photography like this, it can make a real difference.
You don't have to do this of course.
well no , following any advice is purely voluntary - but rich is right that mirror slap is another cause of wobble and thus unsharpness, its more of an issue with slow shutter speeds
Ideally the mirror should be locked up, which it is in live view, and manually focus in live view and zoom in to check focus and manually adjust until your focal point is as sharp as it can be. Then use cable release, self timer shutter...then you are sharp
you haven't experienced "mirror slap" on an image 'till you've shot with something like a Mamiya RB67...
"Mirror slap" doesn't quite do it justice..
Mind you, mirror lock-up is such old hat these days.. my current camera doesn't even offer the setting.