Hi folks! I am an absolute newbie to this board, but I'm impressed with the site,

so I wanted to ask this question that's been on my mind for years. I have looked everywhere to get some info on this unsuccessfully, so I'm wondering if anyone else .
Let me preface the question by saying that I am a Nikon fan

but that's simply because I grew up with an FM SLR to cut my teeth on. That said, I get exposed to Canon products from time to time and I'm impressed by their features.
In 1999, I was on Pikes Peak with my extended family after riding the
Manitou & Pikes Peak Railway to the summit. I get them all lined up for a group photo and my brother-in-law hands me a Canon EOS. I go to take the shot and the viewfinder starts lighting up wherever I look in the frame.

He explains that its part of the auto-focus. I pick out someone in the middle and click a frame or two off before handing it back. Later on, I see an advertisement on the back of Trains magazine for Canon highlighting the same feature. I actually found the ad! I don't think they'd mind me posting it. I left it somewhat big so folks can read the details.

Now, for a long time, I was under the impression that this was a common feature on Canon cameras. I even thought long and often about certain shots it would help with or even rescue. Railroad photography often deals with fast-paced shots of a locomotive quickly moving through your frame. On more than one occasion, I have been burned by the auto-focus failing to adjust at the last second. However, I've found out a while ago that
since going digital, Canon has not included this feature on any camera. Can anyone tell me why Canon quit making this very helpful feature?