400mm f/4 DO IS opinions?

[Fast Glass]

It is indeed the V.1.

Good to know, that was kinda the feedback I was looking for. The techie side is one thing, and I know the V.2 is a dramatic improvement over the old one. But it does give me some insight as to the overall ease of use for this lens. I realize I will be giving up IQ, but being relively light and compact for what it is makes me use it more. It doesn't replace a heavy weight if anything it compliments one.

As to IQ, I can live with the bare lens IQ. The extenders might shy me away a little, but I probably will be using the 1.4 the most often with 400mm coming in second and 800mm last. Although the 800mm end would still be important to me. And the price has dropped so much it's worthwhile to try it and if I don't like it I can sell it and not loose money. But I do like the idea of a field trial.

I'm trying not to be hell bent on getting it and be objectiveas possible and taking in all the feedback, but I remember when this thing was 7k. So seeing one in great condition for $2150 is definitely tempting.