Leica S8 APO B User Manual page 37

Dioptric correction with two adjustable eyepieces (continued)
Checking parfocality
1. Select the highest magnification level.
2. Observe the specimen; if necessary, refocus
it slightly.
3. Change from the highest to the lowest
magnification. The sharpness should be
constant (parfocal). If this is not the case,
repeat this procedure.
Leica S Series User Manual 37