I second or third the Hejnar foot Steve recommended. My 500pf will probably never be on a tripod. I am an old target rifle shooter and shotgunner so I actually use the foot, on all of my lenses with a foot (Nkkor 500 PF, Tamron 150-600, 70-200 G2's), to rest not gripped in the palm of my hand when hand holding which is 98% of the time. The foot helps keep my hand away from the manual focus ring and any accidental focus changes. The Hejnar foot is longer and beautifully machined and Arca-swiss ready.