A tiny object AB to be magnified is placed in front of the objective lens just beyond its principal focus fo’. In this case, the objective lens O of the compound microscope forms a real, inverted and enlarged image A’B’ of the object.
Now A’B’ acts as an object for the eyepiece E, whose position is adjusted so that A’B’ lies between optical centre C2 and the focus fe’ of eyepiece. Now the eyepiece forms a final virtual, inverted and highly magnified image A”B”. this final image A”B” is seen by our eye hold close to eyepiece, after adjusting the final image A”B” at the least distance of distinct vision of 25 cm from the eye.