Conclusion

Although Nikon has improved a number a features, and added several video-oriented functions most of these have been achievable by upgrading the processor. Although some slight gains have been made minimizing shadow noise and expanding the dynamic range, sensor performance is largely unchanged.  That’s not to say the D4s isn’t compelling in anyway, as it is, but anyone that expected significant gains in performance are going to have to wait for the Nikon D5.