An optical element holder includes receptacles for retaining optical elements, and is configured to move a selected optical element into an optical path whereby a light beam passes through the selected optical element. The optical element holder is configured to retain the optical elements in a manner that mitigates or avoids misalignment of the optical elements, thereby mitigating or avoiding unwanted deviations in the path of the light beam. The optical element holder may be part of a microscope or other optical instrument.