Canon EF 400mm f/4 DO IS ii USM lens review with samples (Full-frame & APS-C)

I've been wanting to test this lens ever since I first met it at Photokina in 2014. That was a little while ago now, though - let's see if it's all it's cut out to be on modern, high resolution cameras. Find it here (Amazon affiliate link - I earn a commission on purchases. Be sure to buy the right lens for your system): https://geni.us/canonef400f4doii All pictures shot by me on Canon 6D, Sony a7R II, and Canon EOS M6 Mark ii cameras. Support me on Patreon!   / christopherfrost   ...or on YouTube Memberships: https://www.youtube.com/christopherfr... Equipment I use to make my videos (Amazon affiliate link - I earn a commission on purchases): Canon EOS R5: https://geni.us/CanonEOSR5Body Canon EF-RF Adaptor: https://geni.us/CanonEFtoRF Sigma 50mm f/1.4 'Art': https://geni.us/Sigma50mm14Art Canon RF 35mm f/1.8 IS STM: https://geni.us/CanonRF35mm18Macro Marumi Fit and Slim CPL Filter: https://geni.us/MarumiFitSlim77 AudioTechnica AT2020USB+ Microphone: https://geni.us/AT2020USBPlusMic Rode Smartlav+ Microphone: https://geni.us/RodeSmartLavalierPlus Rode SC3 adapter: https://geni.us/RodeSC3MicAdaptor Zoom H1n Recorder: https://geni.us/ZoomH1nMiniRecorder DJI Mini 2 Drone: https://geni.us/DJIMini2FlyMore As an Amazon Associate, I earn from qualifying purchases. Music: 'Opportunity Walks', Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 3.0 License http://creativecommons.org/licenses/b...