Do any D3 or D700 users ever switch to DX crop mode for the crop factor and "longer" focal length? wondering because i'm thinking about replacing my D90 since i've found myself walking around in the rain much more often than i had thought i would and who wouldn't use that excuse to buy a better camera? however, i mainly focus on wildlife shots so the crop comes in very useful. is it reasonable to use the crop mode just for the purpose? also owning a Fx body gives me an excuse to get the 14-24mm or should i just wait for the D400?