I make a short "making of" video to show how I manage the manually focus on DSLR cameras during i make Birds footage with Super - Telelenses.
My Basic Equipment for DSLR video recording is the haevy Tripod Berlebach UNI 22 c and Berlebach Pegasus Ball head. According to the situation on Site I use the cameras EOS 5d3 or EOS 1D4 with the super telephoto lens EF 600 / f4, partially with 1,4x ore 2x Teleconverters.
Outside the camouflage tent, I fixed on flexible shaft with an clamp, on top is mounted a mini ball head to connecting the "Rhode Videomic Pro" with attached Deadcat windscreen. Connected with the camera, the original sound of the birds is captured.
My "follow focus" consists of a tension strap, usually used for changing air filters in cars. The part is available for 3 euros at the hardware store. The tension strap is simply stretched on the focus ring of the lens. In the Video you can see the Tablet nexus 7 connected with USB Cable with the camera. In the Android App "DSLR controller beta" I made the setting for live view filter. There I use the peaking filter "exposure + grayscale". For me the best optical support to locate focus and move them on the right position.
In the scene with the flamingos, you can see how the peaking filter works when changing follow focus. Well clearly the glittering squares below the flamingos, which makes visible the focus level even on the ground among the birds. This is very helpful for the focus tracking for me. My first focus setting usually is made with autofocus and upright follow focus lever. After this I can turn the lever 180° to the left or right and gets the greatest possible, manual focusing range available.