Safety precautions when using a LEE Filters SW150 stopper for the first time

All of the LEE Filters stoppers have a foam seal around the back of the filter to prevent light leaking in and causing flare, the foam seal has to face towards the camera. On the SW150 system, there is a gap at the sides between the foam seal and the edge of the filter, this is to enable you to be able to slide your filter into the holder more easily.

When using the SW150 stoppers you should make sure that the gap is at the sides of the holder, and not at the top or bottom.

SW150 foam with arrows