What would be the advantage (or otherwise) of using the Novoflex 600mm f8 lens vs the Oly 75-300mm lens, for shooting wildlife. Have the Novoflex system with the 600mm and 400mm and now am looking at 75-300mm Oly, and trying to decide. Have the tripod, gimball, etc. for Novoflex and yes it's heavy but as a prime, can use a Telextender. Any thoughts?