One factor to battery life is your lens. I have a D3 and with the 80-400f4-5.6 lens I get a lot less battery life as the camera battery drives the lens. On a silent wave focusing lens you get more shots. Do you review each shot? I have gotten over 3000 images on one charge on my D3 but that was using a prime lens and not reviewing the images. I would reccomend either the D3 or D3s. I have over 40,000 shots on the D3 and have no complaints.