Wed 23-Jan-13 05:45 AM | edited Wed 23-Jan-13 05:48 AM by icslowmo
If shooting hockey is your main business, and the D4's price isn't an issue, I would say get a D4 for sure as it will give you a little more res and at least a stop of iso performance over the D3. The D4 is said to be on the same level as the D3s which is a stop better then the D3/D700 sensor.... Also the frame rate could be very important for such a fast sport. Also the AF tracking is said to be the best Nikon has right now.
Now another option to be concidered is, you could pick up a longer lens to help reduce the need to crop as much. Such as the Nikon 300mm f2.8 or if 400mm can fill the frame, you could get the Nikon 200-400mm f/4. And by filling the frame more, that should give you better results with your D3....
There is another thread that was started not long ago (Plus many comparisons around the web) that compares the D800 to the D3/D700 and it seems the D800 is about at the same iso/noise levels at the pixel level, but with better dynamic range. What makes the D800 better, would be form reducing the image size (Down-sampling) to the same12mp size, which could give you about 2/3 to 1 stop better iso performance (D3s quality). But that still leaves you with a 12mp file, but it would be a sharper file due to the down-sampling. Take a look at the buttom of the page for iso comparisons: