The Manfrotto SYMPLA Clamp-On Remote Control for Canon DSLRs connects to a Canon DSLR by USB and interfaces directly with the camera and lens firmware to control focus operations and the main functions of the camera. The remote can either be clamped onto the SYMPLA spacer that comes with SYMPLA Adjustable Handles, which are part of most SYMPLA rigs, or it can be clamped onto round tubes, pipes, bars, pan bars or anything similar between 12 and 23mm in diameter.
Direct controls include auto focus, start/stop recording, photo shutter release, live view and live view digital zoom. Other than direct controls, the remote features a customizable focus direction and speed limit, focus memory settings, and fixed or variable focus control modes. It also has LED indicators that display its own battery status, the camera's mode -- "Photo" or "Video" -- and whether the camera is "Recording" when in video mode.
The focus operation is totally remote, without any contact with the camera or lens, and is performed by a 3-step, ultra-precise focus speed. Compatible cameras are Canon DSLRs because the remote is geared specifically for Canon DSLR firmware.
The advantages of this remote are few but huge. Follow-focusing is automated. Lenses can easily be swapped. Extending the distance between the remote and the camera is as simple as using a longer USB cable. And very importantly -- you're afforded more self-reliance.