>>4447218
Firstly you need to account for bellows compensation. If your bellows is 2x the length of your FL you need to add 2 stops of exposure. There's calculators online for this.

Second most lenses are not optimized for high magnification, although some are.

Third most focusing methods on smaller cameras are not precise enough to focus with sub mm dof. You need magnification to focus properly. Try using f5.6-f8 dof preview when focusing. It may help some.

Thirdly diffraction is greatly increased at higher magnifications, so you need to use the sweet spot aperture, or you'll get very soft images.

Fourthly you must use an extremely rigid setup because vibration is greatly exaggerated.

With ultra thin dof you need to tailor your photography to account for it. Shoot flat things, or really tiny things to start out or you'll end up fruatrated with the result. One fun thing to shoot is dehydrated crystals on glass. You make a salt water solution then let it evaporate on a piece of glass.

Pic is one of my 8x10 macro shots using a specialized 25mm lens at over 10x magnification.