Originally posted by macTak Minolta had a technology in some of their latter film SLRs (including my Maxxum 5, now there was a small camera!) called "Eye-Start Automation", which started focusing as soon as you brought your eye to the viewfinder or started moving your eye around, as I recall. According to a manual I quickly dug up: "AF and AE automatically activated/deactivated by combination of eyepiece sensors and grip sensors". As I recall I turned it off and never used it...
Sony used this technology in the A100 (their first DSLR) and I would think in subsequent ones as well.