Here we are comparing two cameras with different body types: Sony A9, which was introduced in April 2017 is a Pro Mirrorless camera with a 24.0MP Full frame sensor whereas Nikon D4, which was introduced in January 2012 is a Pro DSLR camera with a 16.0MP Full frame sensor.
Despite some fundamental differences of these two body types, Mirrorless cameras are becoming serious alternatives to DSLR cameras thanks to their size/weight advantages and recent improvements in their focus speeds , which makes this comparison even more interesting. Fortunately, you can't go wrong with any of these cameras as we rank them amongst Top 10 cameras in their classes. Sony A9 is ranked #7
out of 38 Pro Mirrorless cameras with an overall score of 94 whereas Nikon D4 is ranked #5
out of 34 Pro DSLR cameras with an overall score of 77.
Let's have a brief look at the main features of Sony A9 and Nikon D4 before getting into our more detailed comparison.