Lens advice please. (1 Viewer)

I am seriously contemplating upgrading my main birding lens, I currently use a Sigma 150-500mm telephoto lens with a D90 body & do get reasonable quality images.
Looking for better IQ, my current preferred replacement is to go for a Nikon AF-S ED VRII 200-400mm + TCE 1.4x converter.
A hefty investment so would appreciate some advice in relation to the choice before committing, also like to know whether or not the internal focussing(IF) addition is worth the extra cash?
Many thanks in anticipation of your best responses.
Pepe

You will get various responses depending on the writers preferences/prejudices.
My take on this is that the Nikkor 500mm F4 is about the same size and weight as the 200-400 but gives you the extra 100mm in focal length-which for birding is vital.
The zoom does give you a bit of flexibility at times, but when I had a 100-300 zoom, I was almost always using it at 300mm, and I wish I'd just gone and bought a 300 in the first place.
Another option which is favoured by some is the 300mm F2.8vr with a 1.7 or 2x converter. I use this combination quite frequently as a general walkabout wildlife lens, but I do have an old manual focus 500mm f4 which I sometimes use with both 1.4 and 2x converters when I think I will need the extra reach.

i have used the 200-400 and the 500f4, and the latter wins hands down, for my type of birding.
depends on your type of birding??

Look around on the web for Raymond Barlow's work, including on the birdforum.net's gallery pages. He's done some outstanding work with the 200-400 Nikkor.

Jim

redshank and ptarmigan taken with 200-400
black redstart and uplands sandpiper taken with 500f4

Many thanks for your knowledgeable responses, much appreciated & after looking at the Raymond Barlow stuff will be in better shape to make my mind up.
Great comparative shots Dave, makes me realise at least either option should be worthwhile.
Thanks again for all the feedback.
Pepe