600mm f/4 TC vs 400mm f/2.8 TC: Which Nikon Super-Tele to Buy

Fifteen grand is a lot to get wrong. A pro wildlife shooter who's lived with the Nikon 600mm f/4 TC for years is making the case that it's not automatically the right choice over the 400mm f/2.8 TC — and that distinction matters before you commit. The 400 gives you a stop of light and the reach of a 560mm with the built-in TC; the 600 gives you raw distance but demands more from your light and your back. If you shoot open savannahs and have clean light, the 600 makes sense. If you're in forest edges, golden hour, or need to react fast, the 400 is doing real work the 600 can't. This is the comparison to read before your next big lens purchase, not after the invoice clears.