Today Nikon DF score published at DXOMark lab, the overall score of Nikon DF is behind Nikon D610 and Sony A7R, but the low-light score of Nikon DF is better than its competitors, take a look at the chart below for detailed comparison.
Nikon DF will cost you $2,996 and available at Amazon | Nikon D610 price is approx $1996, available at Amazon || Sony A7R price approx $2,298.00 (body only) available at Amazon, Canon 5D Mark III price is approx $2899.