ricky1980 said:
the argument of using DX lens on Full frame body seems to be a bit of a joke??
why buy a full frame body and cripple it with a lens that can't go for the full frame and still produce the same image quality?!
the OP shoots children outdoor (not sure what this means) and tournaments and races. This suggests 24-70 would suffice and what is wrong with a 12-24? or 17-35? they are all very useful lens cover very good focal range in Full frame. 12-24 might be a bit wide if the OP doesn't do landscape. but certain 17-35 would be ideal in Full frame situation as well as in DX mode.
Definitely build up your FX lens and then change the body. The upgrade in lens will also result in sharper images as someone mentioned before, the lens will have much better edge sharpness than DX lens. If not for the fact D800 can step down the sensor i.e. crop the image, would anyone recommend DX lens on FX body...NO you wouldn't cos there will be a ridiculous black ring!
the same approach still applies. This gimmick of cropping the image for DX lens, i just don't buy it!
EDIT: I didn't quite appreciate the D800 is 36 mpixels...that's quite impressive. For those people who thinks more pixels is better, you are wrong. more pixel only means you can make larger prints without suffering image quality degradation when printed. My D90 can print A2 sized prints just fine without any issues. @ A1 you can see the pixels - that's standing an inch away from the print and looking at it with a sharp eye
I'm going to correct some points here.
"Children outdoors, tournaments and races" indicates a telephoto lens. Certainly the 24mm end of a 24-70 isn't going to get much use.
The 12-24 is a DX lens NOT full frame. 12mm would be insanely wide on FF. "Very good focal range on FX?" Not so much.
I would like to see evidence of why FX lenses are better than DX lenses on DX. They will be, in general, larger and heavier than their DX equivalents, and often the wrong focal lengths (24-70 being a good example - not wide enough on DX). Are you saying you've really tested the FX 35mm f2 and the DX 35mm f1.8 and concluded that the f2 is sharper? I'd love to see the results, seriously. It would make me switch to the f2 in a heartbeat if true. Is suspect, however, that the DX lens is better for DX, being as it is faster, insanely sharp and AF-S.
The thing to do is have the right lenses for the camera you have. Some lenses work well on both systems - the 70-300 zooms spring to mind here - but FX 2.8 zooms are overkill on DX - the suggestion of using the 14-24 on DX is risible. However, one is forced to use FX primes on DX in most situations (20mm, 24mm, 28mm, 85mm) so that's where I would be investing lens-wise if I had an eye on upgrading to FX.
Don't sweat the DX crop, I can't imagine many people using it.
"For those people who thinks [sic] more pixels is better, you are wrong." [facepalm] You contradict this statement with your next sentence, helpfully removing the need for me to correct it. I agree pixels aren't the only consideration, I too have made giant prints from a D90's 12MP, and often it's the *quality* of the pixels that matter, rather than quantity, but still, all other things being equal, more is better.
In summary, to the OP, if you want to make the switch to FX, just do it, but I would go D700 and have some money left over for lenses and a computer upgrade rather than be stuck with massive 36MP D800 files and lack the computing power to edit them on.
