LOMO SF-AO2X Auxiliary Objective (2X) for SF-100 microscopes

This 2x barlow lens is a nice addition to the Lomo SF-100 stereoscope. It not only doubles the magnification, but also increases resolution. With it the top power is 200X, and seems sharper than 100X did without it. Of course with it the focal distance is shorter and the depth of field is a bit shallower. That is a normal tradeoff. Pros: increased power and resolution Cons: shorter working distance and less depth of field