CyberDyneSystems wrote in post #17951424
Here it is, step by step:
PART ONE. C.Fn I # 14:- Mount your fastest aperture lens, f/2 or f/1.8 (don't worry about your long lens, it's wide open aperture we need)
- Set your camera to AV, and the aperture to wide open.
- Go into menu, Custom Functions, CFN I (exposure) #14
- Press the set button, turn rear wheel to highlight "
Register" press "set"
- Select the top option "
With AE Lock Button (AF ON) " press set.
Now whenever you press the * button, the camera will go to AV mode, wide open on any lens mounted, and begin to AF. Step 2: Set * AE Lock to activate registered AF POINT- Menu, Custom Functions C.Fn III (Autofocus/Drive) #11
"Switch to registerd AF Point"- Press set, scroll with rear wheel to "
2: Only while <*> is pressed "
Now when ever you press and hold the * button, camera will go to AV, open aperture to wide open, and start auto focusing with the registered AF point.STEP 3: Set "Ring of fire" or "Hail Mary" as your "registered AF point"-Hold camera up to your face so you are looking through the viewfinder.
- Press the AF Mode selection button (last thumb button on right, past *, it's also the + magnification button. Your current AF selected AF point should light up. Now use the main dial (shutter button finger dial) or joystick to scroll to the outer edge of the AF points until the entire ring lights up in an oval, or "ring of fire".
- Once the "ring of Fire is lit up, press and hold both the +(AF selection/Magnification button with your thumb, and the ISO button with your shutter finger and hold. The camera will NOT let you know you did anything right

BUT! You have just registered All 45 AF points or "ring of fire" as your "registered" AF point.
Now when ever you press and hold the * button, camera will go to AV, open aperture to wide open, and start auto focusing with the registered AF point, AND your registered AF point is RING OF FIRETesting:
Now, pick up your camera, press the center of the joystick to select the center AF point.
Set camera to Manual exposure, set a stopped down aperture (say f/11) Set a shutter speed.
Now looking through the viewfinder, use the AF ON button, and notice, you have your manual exposure set, your stopped down f/11 is set, and whatever shutter speed you set.
Pint it at a few things and test this out.
NOW > Move your thumb from [AF ON] to * and press! Your camera will suddenly set aperture to wide open, you will be in AV, and instead of the one center AF point you will be in ring of fire! Move your thumb back to [AF ON] and you are back in manual, stopped down to f/11 etc.
THAT IS THE HAIL MARY SET UP.