parfocal objectivesmedical dictionary

<microscopy> Objectives which are mounted so that only a small adjustment of the bodytube and stage is necessary to focus after changing from one objective to any of the others. They are mounted in such a way that the back focal plane is in the same position on the optical axis of the microscope for each objective. Objectives used on a rotating nosepiece are usually parfocal. Eyepieces are also parfocal within any given manufacturer's

(05 Aug 1998)