400mm or 100-400mm

I'm going to offer a slightly different suggestion.

Assuming your sig line is correct, why not get a 1.4x and use it with your 70-200 and sell the 70-300. That would give you a nice range with the added benefit of being f4 throughout the range.

Of course, that depends on the version of your 70-200.

The 70-200mm I have is: 70-200mm 1:4 L IS USM

4/56

Okay folks you saw it here first, it's the end of an era after years of saying "get the prime"..

Now that I have the MkII 100-400mm in my hands. this is THE lens I would recommend.

I'm from Missouri (means I haven't used the 100-400 II), so...

400 5.6