I experienced rings with the Valoy II which I just recently started to use. I used 3 or 4 pieces of post -it tape to the back edge of the negative holder. This holds the condenser just off the negative. To the right of the Valoy's head is silver lever which raises the head. You can position the lever so the head is not completely down on the negative. In theory, I risk loss of sharpness. In practice, I don't see any loss of sharpness. I use a grain focus device. BTW, the aperture illuminated El Nikkor f/2.8 is a great lens on a Valoy. Edge to edge sharpness at f/4. Easy to see the apertures.