Canon EOS 5 - Manual (Page 37)

If the camera cannot determine which AF
frame you are looking at:
1) “ 1> ” blinks in the viewfinder and the
camera automatically switches to auto­
matic focusing point selection mode (refer
to page 26) to select the focusing point.
After focusing is completed, “ i> ” will
continue to blink in the viewfinder but it is
still possible to use the eye-controlled
depth-of-field check function. To return to
Eye Controlled Focus mode, remove your
finger from the shutter button and then
press it again halfway.
2) Different shooting locations can conceiv­
ably change the state of your eye and af­
fect Eye Controlled Focus operation.
When shooting in a location with a differ­
ent light source, perform the calibration
procedure again at the calibration number
you are currently using (refer to page 16).
Each time a calibration is performed the
camera “learns” the different states of your
eye, improving the Eye Controlled Focus
operation.