i have been testing a variety of cams from the mark 2 and 3's, to sony ax100 baby 4k etc. today rigged the really lightweight canon sl1 with the 10mm IS STM lens...equiv to 16mm wide, very nice rectilinear wide look. autofocus is silent, good within reason, grabs faces nicely. stabilization is sweet. slow lens but crisp, especially for 300 bucks! the freefly mount plate is just slightly too big to open the battery/card door without dismounting tho, eh! adding a small cheeseplate to change that pain. the sl1 has manual audio level, and attenuation, not bad on initial tests, input jack, auto leveling too if needed, doesn't pump if u choose the attenuation. no headphone jack, eh. use an hdmi monitor with sound/headphone. wireless receiver mounted on liftbar with headphone jack helps too. not clean hdmi during shoot but is full screen 1080 upon playback. the sl1 is so stinking small and lightweight, flies friendly on the arms. both stm lenses are also featherweight. so, useable manual audio input for walk and talks, autofocus that follows faces if u choose, fully manual video control, weighs 13 ounces without lens, available cheap 16mm equivilent smooth non stepped auto focusing wide angle canon lens, touchscreen sharp lcd goes dark when feeding hdmi eh. u can use any ef lens and they will focus! but they step rapidly, not smooth. excellent for still pix shooting tho. not for video shooting. anyhow, if this is the way the mark 4 is headed, way cool.