i considered the D800 and the D4. i do a lot of wildlife, especially birds, and a fair amount of sports and scenic shots. ended up with the D4. No question the D4 is the dest tool for the job. the D800 while high resolution, just cannot compete with the D4 for burst shooting of moving subjects, and the D4 does just fine for scenics. The AF, low light capabilities of the D4 are just superb, and with its buffer capacity, you will find it hard to fill, especially if you buy one of the XQD cards, which are getting cheaper all the time.