I remember when 75-300mm first appeared in any sort of quality, for 35mm film bodies. If you wanted more, you bought a 500/600mm mirror lens!
Now folks with crop bodies are complaining a 300 is too short?
So go and buy a 600 f4. That's about the only thing that you seem to want! Though I did see a Nikon 800mm in the Silverstone grandstands at Britcar... Then again it was on a D3.
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