SOM BERTHIOT STEREO MICROSCOPE LENSES PROJECTION? COMES A SLIT LIGHT THROUGH

The 2 lenses while looking through they show only a small slit of light coming through. See last picture. The two identical lenses are 57mm in hight and have a 20mm diameter the lower has a 24mm diameter. The corse lower part is 24mm in diameter, both move smooth and make the slit smaller.

Elements are clean and bright, show no anomalies.

Lens shows some signs of prior use and is overall in good condition. Shows minor scuffs marks, minor scratches, no dings, no indentations, some nickel plating rub off. The elements are in very good condition. No cleaning marks, no scratches, no haze, no fungus, no separation.