Another eyesight trap

[dpex]

Way back in the late 80's when I was entertaining childish delusions of becoming the word's greatest clay-target shooter, I discovered another rather nasty little trick one's eyes can play. This one is particularly pertinent when riding with your visor in the down-and-closed position.

But, to better explain the effect, try this. Stand at a window upon which you have placed a small dot (a dot of birdshit will do, in fact any dot). You don't even have to place a dot if there's already one there.

Now then. line up the dot with another object at say, 100/150 metres distance. Focus on the far object while acknowledging the position of the mark on the window-pane.

Without moving your eye-line, change your focus from the distance thing to the mark on the window-pane, and observe it is now nowhere near in line with the distance marker. It will have gone left or right of the distant marker, and up or down as well.

Now allow your focus to hold the mark and move your head till you can line up the mark with the distant object. Without moving your eyes, allow your focus to go back to the distant object.

You will see the mark on the window pane has gone the same distance out of line with the distant mark, but the exact opposite way.

"And so?" I hear you ask.

So think about this. You're riding along (unless you have a Triumph, then you're probably pushing it along) with your visor in the down position. It's got a few bug-splats on it. You're a bit tired, a bit dehydrated. You think you are seeing the correct position of the dangers ahead, but in fact, unconsciously, your focus has discovered a bug-splat.

Now the dangers ahead are actually in a completely different (observed) position to their real location, relative to your line of travel, to where they were when your focus was on them, not the bug-splat. At least, that's the new picture your brain processes.

When shooting at a clay-target, you either focus on the target and let your secondary focus 'Know' where the barrel is (relative to target travel) or you focus on the barrel and allow your secondary focus to 'Know' where the target is, relative to the barrel.

By switching focus just as you shoot, you miss cos the target is well away from where you perceive it to be.

Freaky things, these eyes, eh?

[Slyer]

So the same sort of thing would happen to scopes too right?

[slofox]

Clay target shooting has been one of my interests too dpex......
I had trouble with target focus because I have a visual deficit in my R eye which is also my dominant eye. I have a "hole" in the upper left quadrant of my R eye vision as a result of a retinal detachment many years ago....I also shoot right handed. I found that the L eye kept telling my brain that it could do a better job of tracking the target than the R cause it had full vision....so there was a conflict between the two.
For a while I tried closing the L eye. But then I would lose sight of a target that flew up and left into the "hole".....so I had to go back to both eyes open.
I eventually resolved the conflict by keeping both eyes open (as everyone says you should) but I had to make a conscious effort to 1. move the focal point out from the end of the gun, and 2. to make sure that the R eye was dominating proceedings. This I achieved by drooping the L eyelid a little until the R took over and then opening L again.....very complicated. No wonder I went back to riding bikes.......