a piece of bicycle inner tube about 1/12 to 2 inches long.. diameter well measure your lens diameter. for that...
one Camera Cap. and a large cable tide.
1st dismantle the lens by taking the back off and inner rings. and outer ring.
put lens in side one end of the inner tube.
at the other end place the camera cap. after you have removed the inner bit or center of it. leaving you with a ring.... see picture.
secure the cap with a large cable tide and go and take pictures... this really works...... have fun.