I don't know that there's that much difference in IQ with the 400 f/5.6 and the
100 - 400 IS. I have both and find the 100 - 400 is the lens I use on my second camera. I Usually have the Mark III and 500 IS with 1.4x tripod mounted and the Mark II N and 100-400 IS around my neck. The 400 f/5.6 is a dust collector for me. Your mileage may vary I just find having the zoom so much nicer. The 400 Prime does focus a little faster > But were not talking enough to make me want to give up my zoom.
Good luck and good shooting > Either way you've got a great lens to shoot with
Man guys ,
let him enjoy his first L lens in peace!
Just because you feel insecure about yourself because YOU dont have the 400 5.6 that does not mean we need to post a slew of 100-400 images to prove it can take good pictures 2!
Oh and about the L thing...dont you love that smell when you first open the padded case it comes in for the first time...You cant own just one :-)
I just find having the zoom so much nicer. The 400 Prime does focus a little faster > But were not talking enough to make me want to give up my zoom.