I'm gradually making the DX --> FX transition. I've had the 24-70 and 70-200 for a while now. Apart from a repair issue, I seem to have a D3. I have a 12-24 f4 lens I use with my D90. Honestly, I don't use ultra-wide much as it's not useful for bicycle racing which is 90% of what I do, but it IS really nice for architecture, indoors, kitchens, and presumably also for landscape. I have held off on buying a FX ultrawide zoom because I have already drained the bank on the D3 and the "right" solution for ultrawide -- a 14-24 -- is such a bank breaker ($2k!). I was researching what I can get for my 12-24 -- apparently these sell for something like $600-900 and mine is in really nice shape -- vs. the cost of the various FX ultrawide options. It seems like it might make sense to sell the 12-24 and purchase an 18-35 f3.5-4.5. They sell for $600 new. Having one of these would mean I don't have to carry two bodies and I'd get the 3-stop low-light advantage of the D3. Any opinions on the various ultrawide FX choices? 14-24 f2.8 seems like the undisputed best choice but the price is too much ($2k) -- no worries that you can't use filters and I don't care that it is heavy. 16-35 f4 @ $1200 seems reasonable 17-35 f2.8 @ $1800 seems like a dumb idea compared to the 14-24 18-35 f3.5-4.5 @ $600 for a small, light lens seems like the ticket -- any concerns about this lens? I am not a pixel peeper. What's wrong with variable aperture? I could get one of these new for less than I would sell my 12-24 DX lens for. Is the 18-35 a reasonable choice? Am I going to regret not having the 14-24? I would be using it for interiors, some architecture, and some outdoor shots, but honestly I will use it MUCH less than my 24-70 and 70-200.