The eyepiece (ocular), ï It magnifies the primary image produced by the objective; the eye can then use the full resolution capability of the objective. ï The microscope produces a virtual image of the specimen at the point of most distinct vision, generally 250 mm (10 in.) from the eye. The eyepiece magnifies this image, permitting achievement of useful magnifications. ï The standard eyepiece has a 24-mm-diam field of view; wide-field eyepieces for plano objectives have a 30-mm-diam field of view (Fig. 7), which increases the usable area of the primary image. ï The simplest eyepiece is the Huygenian, which is satisfactory for use with low- and medium-power achromat objectives. ï Compensating eyepieces are used with high NA achromat and the more highly corrected objectives. Because some lens corrections are performed using these eyepieces, the eyepiece must be matched with the type of objective used.