I use my DSLR camera to shoot videos of moving subjects (such as a car), and sometimes I pan the camera to track the subjects as they move.
The problem I have is that to track the subject, I have to watch the video screen and coordinate my hand movements. But the video image has a non-trivial lag. Furthermore I usually use image stabilized lenses (and mode 2) which reduce shake and improve the watchability of the recorded video, but adds more lag and non-linearity to my panning movements.
So the proposed solution I came up with is to have a separate optical viewfinder, so that I can track the subject without any lag or stabilization. Ideally such a viewfinder should be mounted on the hotshoe. But searching around on the Web, it seems there aren't many reasonable products for this application (e.g. Olympus-specific wide angle viewfinder, >100 USD), and it seems not many people have considered using an optical viewfinder for video recording.
My question is, how would you approach this problem?