Really wish I could give 5 stars, but I have to subtract 1 star for design with the 100-500. Must zoom out to 300mm to attach. But, it’s really sharp. I think the combo I just described makes the 100-500 sharper with added boca. Go figure with slower F stop.

Buying an extender over a longer lens for financial reasons can make sense. The very long focal length lenses are considerably more expensive than extenders. Using extenders to save space (vs. carrying a second, larger lens) when traveling or hiking can be a good decision.