The most versatile tool for macro work is a set of 3 extension tubes.
Place them between the camera body and prime Lens, have a diaphragm setting as low as possible if you are working without flash, and combine it with a long exposure time. For flash shots the diaphragm setting has to be correspondingly greater compared with values calculated from the Guide number and distance. Computer flash units require another calculation.
Use tubes individually or together for maximum magnification. The following table will help work out the multiplication factor using a standard 50mm lens.
|Extension factor (intermediate ring)||Multiplication factor||Necessary multiplication for diaphragm response exposure time stages|
|13+21 = 34mm||2.56||1.25|
|13+31 = 44mm||3.84||1.80|
|21+31 = 52mm||4.32||2.10|
|13+21+31 = 65mm||5.38||20|