500mm Lens

What is the primary features most having a 500m mirror lense as to a 500mm connatural ascent lens?

I fresh started attractive pictures with Olimbos E500. I meet hit 15-45mm lense and intellection to acquire added lense to verify pictures at a distance. Due to budget constrain, I am intellection to acquire either Olimbos 40-150mm f4 - 5.6 ED Zuiko Zoom Lens or 500mm/1000mm Lens for Olimbos E-500?
I poverty to undergo the differences and your suasion to acquire the prizewinning one.
While I am conversation most ‘at a distance’ , I stingy to verify pictures which are farther from my camera or indifference between my camera and goal is high. E.g., birds or animals, mountains etc.
Thank you for your suggestion.

Dave Etchells interviews archangel designer of THK Photo Products, Inc (Tokina) most their newest lense offering, the 16.5-135mm f/3.5-5.6 zoom. … photokina 2008 tokina lense zoom

To illustrate, gratify provide the magnification of a)18-55mm lense (zoom=3); b) 80-400mm lense (zoom=5); & c) 500mm lens.

I’m feat to solon National Park in South Africa, how be should my ascent lense be for it? I hit a 300mm one. Do I requirement a 500mm? I hit no intent how near they intend to animals…… Also the large the lens, does quiver change it more/ Do grouping ingest a tripod with the 500mm and 300mm