Thanks for that . It depends how close you're getting to your subject. The D4 will crop quite well, so if you're relatively close then a D4 will suffice and will handle low light situations better. But many wildlife photogs (including myself) prefer the extra reach and higher MP gained from aps-c frames. I have compared side by side bird image shots with my D810 and D7200, my conclusion is the D7200 for birding, every time. Just my point of viewThanks jay_dean. I do mostly wildlife, so there will be some cropping. Guess it is best to stay with crop sensor bodies. I should just ask you my questions,you always have a good answer. Thanks again.