http://www.infographicsarchive.com/...ositions-and-responsibilities/#prettyPhoto/0/
Scroll down to the JLA image. Finite number of cameras, with only 3 ice level (plus an occasional roaming handheld). Even if there are cameras on both blue lines, they are not at both sides of each line, and the trailing ref has to switch back and forth, and of course may be in the middle when a play happens.
You said if there is a camera directly behind the ref, then it can be used to make a better call. And yes, you are right. What we are saying is that there are many many spots the ref can be where the camera does not have the same angle, and that often the ref has the better one ('cause, you know, the ref positioning hasn't been worked out over the course of the sport to be optimal for making the correct calls or anything).
I'll continue this with you, because I sense we can have a different type of discussion.
That's a good chart to show some of the angles, but we know those cameras from that company don't represent all the cameras at the leagues disposal. They have access to the arena cams, the NHL's cams, and each broadcasting stations cams.
For instance we know there are more than a few angles not pointed out in that chart from past knowledge, and also this video from the situation room.
[NHL]225265[/NHL]
Specifically at :34 just for a split second they show an angle that looks to be lined up with the redline at center ice but is near the top of the glass level, not one of the two cameras in the upper level in that chart. I believe they also show this lower red line cam for faceoffs sometimes during tv broadcasts.
Then at :38, in the bottom right corner, there's an angle that looks like it's inside the blue line at near ice level.
Also that chart shows the cameras behind the net, but doesn't show the cameras above the net, which we know is over both goals.
There's also a goal line cam that's not on that chart, that we've all seen before, and you can see at 1:15 in the video.
Then there's an angle they show at 1:39 that's clearly not one of the angles behind the net, because it's at ice level, below the glass, from the other end of the rink.
We also know there are cameras along the benches that pick up the play on the ice.
There are also cameras in the penalty boxes.
Now an angle like the penalty box cam isn't going to help goal reviews, but it shows that chart isn't nearly complete with all the camera angles the league has access to. I have feeling there's even more than in the video too, but that's just a hunch.
Also, Rogers added six new angles this year to the games they will be doing, including ref cams, and an arial cam.
If it were an issue where maybe there were just a couple cameras along the blueline, maybe you could argue that the back official might do just as good or better of a job at judging the play on ice from 75 feet away, because like you said one angle could be obstructed.
But my point is that with the sheer volume of camera angles, and the ability to slow mo, and zoom in HD, and that they're higher and less likely to be obstructed by legs and sticks at ice level, it has to be considered a more accurate way to over turn the original refs call close to the play.
It's just highly unlikely that all the angles will be obstructed, and the ref outside the blueline will have the golden sightline. That's kinda like the magic bullet theory.
If the cameras have that much better of a chance at seeing the play, and they can't conclusively see it, then they simply shouldn't let the outside ref with one angle at ice level, in real time, over turn the original call. The chances that he both saw it better than all the cameras,
and got it right at real speed, while the closer ref got it wrong, are very minuscule I think.