While the 5D Mark IV has the specifications that create marginally higher-quality images and videos, the 6D Mark II features more modern controls and options that contribute to ease of use. Which of the two cameras to get really depends on how much time and effort you invest into photography or filmmaking. -4K crop: the 1dx mk ii has a 4k crop factor of 1.3x, whereas the 5D mark iv has a 4k crop factor of 1.74x or something-120fps: the 1dx mk ii can do this at 1080p, while the 5d mark ii can only do this at 720p . As I currently shoot 1080p for clients that are ok with DSLR-level image quality, the 5D mark iv looks great to me. Canon 5D Mark III vs. Fuji X100S image quality 09 January 2014. Canon 5D Mk III vs. LEICA M 240 vs. Sony A7 Image Quality Comparison 19 December 2013. Canon 6D. Similar image quality smaller, lighter package with a few less controls, but with added Wi-Fi and GPS. Canon 5D Mark III versus Canon 6D. aje44F.