Hi the original strap that came with my d3100 isnt as secure as i would like.Sometimes when ive got my camera over my shoulder the strap has slipped out of the metal rings on the camera.this has resulted in me nearly dropping the camera a few times.Does anyone know of anything more secure and where to get it. ive seen straps with metal swivel ends which look more secure but do not know where to get them. any ideas? thanks