parfocal

English - English

Definition of parfocal in English English dictionary

Having multiple lenses that have corresponding focal points in the same plane

With the lower focal points all in the same plane; said of sets of eyepieces so mounted that they may be interchanged without varying the focus of the instrument (as a microscope or telescope) with which they are used

This is a focus issue When changing from one objective to another, the new image should be either in focus or close enough so that you can refocus with only minor adjustments Most microscopes are parfocal

A term applied to objectives and eyepieces when practically no change in focus has to be made when one magnification power is substituted for another