Nikon 200-400mm + TC1.7 or Nikon 300mf4 +TC1.7+D7100

I am having a palpitations on my chest since I have in my mind the desire to buy a 200-400mm f4 VR I.

I found for sale this lens and the seller is asking $4000 for it, I already have the TC1.7 and the 300mm f4 and it is a nice and sharp copy.

My dilemma is if I buy the 200-400 I will use it with the TC 1.7 on my D600, unfortunately there is no too much information out there about the performance of this combo, some reviews state this combo delivers very bad results but some photographers are reporting that D800 and D600 with this lens and TC1.7 works better than older cameras because the advanced auto focus system.

So, doing some numbers I have two options:

Option 1

The D600 + 200-400mm f4 + TC1.7 is giving 680mm at the long end. cost $4000

Option 2

The D7100 + 300mmf4 + TC1.7 is giving 510mm (765mm in 35mm). cost$1200

I know the zoom is very convenient in some situations but the cost of this option is $4000.

I will use this set up for wildlife and large birds.

I would like to know what do you think and I really appreciate if you can give me some advice and feedback about it.

Thank you for your time and have a great day.

Marcelo

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