EOS HD by Phil Holland
I was messaged this today on the site from Phil Holland - thanks Phil!
He's done a great job explaining and demonstrating his rig, with a general overview of why one is useful.
I'm all for keeping this kind of equipment at a minimum for the job in hand. That's why Phil's video is good - because it's a nice practical rig and not too bulky or complex, plus it can be stripped down quickly and easily.
Rigs are something a DSLR really benefits from because they lack so many of the bells and whistles on professional video recording systems.
For handheld work they give extra stability to the image, there is nothing worse than the quick shaking you get from lightweight DSLRs when held purely by hand without any kind of rig. Also the shoulder mounted rigs and viewfinders are good for stability because they give the DSLR a mounting point and they move with your head or shoulders, not on the end of a shaky outstretched arm.
Rigs often feature rails which are handy because they're capable of extending the life of the camera mount when used with heavy lenses. Sometimes it may be mandatory. I have an Isco Centavision and an old Zeiss anamorphic and these are just too heavy to not need a system of rails. My Lomo anamorphic comes with a baseplate attachment for rails too so I'll definitely be in need of some rails on EOSHD.com soon.
As more and more DSLRs get good live HDMI out-feeds, you can now also attach monitors and EVFs to your rig, which enable a viewfinder to the side of the camera rather than directly behind it at the back. These are especially useful for mounting the camera on a shoulder support because it means your head is naturally to the left or right of the camera in that position.