Some Nikon Df camera size comparisons (click on images for larger view):
Nikon D4 vs. Nikon D610 vs. Nikon Df vs. Sony a7:

credit: dicahub
Nikon D610 vs. Nikon Df vs. Sony a7r:
Some Nikon Df camera size comparisons (click on images for larger view):
Nikon D4 vs. Nikon D610 vs. Nikon Df vs. Sony a7:
credit: dicahub
Nikon D610 vs. Nikon Df vs. Sony a7r: