It all boils down to pixel quality since the amount of pixel is the same on both bodies. Put it otherwise, what is the gap in noise/DR between DX and FX pixels at low ISO? Most analysis I have read claim that it is around 1/3 stop considering a given technology. It means that - in theory - a D300 at ISO100 would be better than a D3 at ISO200. Since the D3 doesn't have a real ISO 100 setting, this would indicate that the D300 would in fact be able to achieve better absolute low ISO image quality than the D3.
You are confused about the "native" ISO on the D300, but nonetheless I think there are other issues to consider beyond the sensor in this discussion that may well have a greater bearing -- namely the lenses used to attain a given field of view.
This isn't the case in reality because they are using different sensor technologies. Looking at it the other way around, Nikon had to develop better sensor technology for the D3 in order to justify the price premium of the higher end body accross the ISO range.
As I understand it, the D3/D700 sensor was designed to deliver optimum results under artificial lighting, particularly when the ISO is pushed. For landscape photography using base ISO that makes comparisons with the D300 less of a slam dunk than many seem to think it is, at least as far as the sensors are concerned. Now the D300 sensor does not appear to be optimized for daylight either, but I don't think any DSLR ever has been (they are more generalist in the design of their sensor's spectral characteristics) and in that regard DSLRs haven't fully matured yet.
More pixels per unit area, which is essentially of no practical consequence other than the potential impact on pixel quality discussed above.
Sorry to disagree with you, but (as I already wrote) if you are attempting to get as much reach as you can from a given focal length than having more pixels does make a difference, and the difference can be significant since the D3 or D700 in DX mode delivers about 40% of the pixels you get compared to using a D300.
Anyone used a d300 or d3/d700 that could comment on this?
This is what Thom Hogan wrote today at DPR about this: Other than the highest ISO values and a teeny bit of DR, the D700/D3 don't do "critical things" better than the D90/D300.
You can read the entire post here: http://forums.dpreview.com/forums/read.asp...essage=30039078
I could have bought the D700 this summer, but I passed on it because I am getting excellent results with my D300. Instead I bought more lenses and I am going to wait until Nikon releases a smaller body, high MP FX DSLR that I can afford; I'm hoping that it will be around $3000 and available before next winter.