If I set out to do this picture using the D700, a 12 megapixel camera using only one picture, since the picture has a dimension of 1:3 as compare to the original format of 4:6, the picture would only have 1/2 of the original pixel size, 6 megapixel. On the other hand, the merged photograph has about 20 megapixel. It is even larger than the picture from the 24.5 megapixel camera D3x, because when the picture from D3x is trimmed to 1:3 dimension, it will have only 12.25 megapixel.
Some details of the technique: 1. Try to use the same exposure for both pictures; 2. Try to place the focusing point for both pictures at the overlapping area; 3. Try to use telephoto lens to get the detail; 4. Try to us "cylindrical" during photomerge in Photoshop CS4.
We will go to Yosemite latter next week to shot landscape for fall color. We hope we will put this technique into good use.