True 100% parallax free sight?


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zollen
April 23, 2011, 01:11 AM
Is it possible to have a true 100% parallax free sight/scope (regardless of distance)??



1. Mirror#1 to take what the a gunner would see through a view finder
2. Mirror#2 to reflect the image of Mirror#1 back to a gunner eyes
3. Superimpose a red dot on Mirror #2 before reflecting the image back gunner eyes.

Do you think the above approach would solve the parallax problem regardless of distance?

Here is the conceptual design

http://img829.imageshack.us/img829/3272/reddotdesign.png

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gathert
April 23, 2011, 02:15 AM
Parallax comes from lenses and I see no lenses.

zollen
April 23, 2011, 02:23 AM
The proposed concept utilizes only mirrors for reflecting images.

gathert
April 23, 2011, 02:25 AM
So parallax isn't even an issue with that type of sight. I would prefer open sights to one like that, but thats just me.

brboyer
April 23, 2011, 03:02 AM
That would be like looking down a very dark straw.
You got to have some lenses, otherwise the thing would be unusable due to dust/dirt debris, and one you introduce lenses into the design, you are likely going to introduce parallax.

General Geoff
April 23, 2011, 07:27 AM
I thought the point behind any red dot sight was to counteract parallax (as the red dot stays on target regardless of viewing angle)...

gathert
April 23, 2011, 11:28 AM
Most red dots I've used, when you move your head any on the stock or side to side, the dot moves as well. So unless then gun is perfectly lined up all the time, you wont be hitting POA.

dmazur
April 23, 2011, 12:39 PM
Here's a link to a manufacturer of holographic red dots -

http://www.eotech-inc.com/page.php?id=11

I believe that conventional 1X red-dots (Aimpoint) are almost parallax free, as they are designed with compensating optics of some type, but the holographic red-dots achieve complete elimination of parallax.

Here's a diagram of the Eotech from Wikipedia -

http://en.wikipedia.org/wiki/EOTech

It does appear to be made up of mirrors. And a special holographic grating, and a laser diode. :)

zollen
April 23, 2011, 02:09 PM
Most red dots I've used, when you move your head any on the stock or side to side, the dot moves as well. So unless then gun is perfectly lined up all the time, you wont be hitting POA.
Agree. I just don't understand why many sights/scopes are being marketed as parallax free. The reticule/dot of these commercial optics move as well (w/wo magnification) when eyes are shifted from side-to-side. My concept addresses exactly this issue.

It would be really nice if you could quickly locate + aim at your target without even lining up yourself with your sight. Imagine concealing yourself behind a corner and exposing only your firearm for engaging targets, this would require a bit of training but at least this concept allows you to achieve that.

zollen
April 23, 2011, 02:11 PM
That would be like looking down a very dark straw.
You got to have some lenses, otherwise the thing would be unusable due to dust/dirt debris, and one you introduce lenses into the design, you are likely going to introduce parallax.
The very dark narrow straw issue could be addressed with some form of internal illumination.

General Geoff
April 23, 2011, 02:20 PM
Looks like the Eotech holographic sights are what you want.

zollen
April 23, 2011, 02:30 PM
Looks like the Eotech holographic sights are what you want.
You mean EOTech reticule would not move even if I shift my head from side-to-side? It always stays on the target?

DoubleTapDrew
April 23, 2011, 03:14 PM
You mean EOTech reticule would not move even if I shift my head from side-to-side? It always stays on the target?
The reticle moves but it moves with your eye so it stays on target regardless of your head position

Here's a youtube vid showing what I'm talking about:
http://www.youtube.com/watch?v=kkNNRWpwQKk&feature=related

General Geoff
April 23, 2011, 03:22 PM
Yeah, in other words, the bullet will hit where the dot is, regardless of your viewing angle (ballistic drop notwithstanding).

zollen
April 23, 2011, 04:15 PM
The reticle moves but it moves with your eye so it stays on target regardless of your head position

Here's a youtube vid showing what I'm talking about:
http://www.youtube.com/watch?v=kkNNRWpwQKk&feature=related
Thanks. It really does stay on the target regardless of the shifting of the camera. I assume EOTech sights are parallax free regardless of distance, am I correct? How about Aimpoint?

dmazur
April 23, 2011, 04:34 PM
While Aimpoint sights are not holographic sights, they are nearly parallax-free in the 1X models. If you go off-axis far enough, there will be parallax error. I believe the error is due to imperfect corrective lenses, not due to theory.

Here's a link to reflex sights, which does a pretty good job of explaining how they work. Aimpoint sights are reflex sights. -

http://en.wikipedia.org/wiki/Reflex_sight

In my limited understanding of the terminology, AO telescopic sights can be adjusted for no parallax error at one distance. The distance can vary, but you will have eliminated parallax at only one distance.

Parallax-free sights have no parallax error. By definition, distance is not a factor.

zollen
April 23, 2011, 05:04 PM
My job is done!

JohnKSa
April 23, 2011, 05:21 PM
Most red dots I've used, when you move your head any on the stock or side to side, the dot moves as well.The important thing is whether it moves on the target image. Holographic sights do have red dots that appear to move with your head, however the key is that while they appear to move in relation to the sight (with relation to the viewing "window") they stay on the same place on the target.Parallax comes from lenses...You can have parallax without lenses, a simple needle dial gauge will exhibit parallax since the needle indicator is not in the same plane as the marked dial. Viewing it from the front will provide a correct reading. Viewing it from the left side will cause the needle to be superimposed over the dial too far to the right resulting in an incorrect reading and viewing from the right side will have the opposite result.

The same applies to scopes. If it's set up so that the reticle doesn't "live" in the same plane as the target then there will be parallax. Typical optical scopes have adjustments to allow the shooter to eliminate parallax at a specific range. Good quality holographic scopes eliminate parallax entirely by effectively putting the reticle and the target image in the same plane.

benEzra
May 1, 2011, 10:51 PM
Is it possible to have a true 100% parallax free sight/scope (regardless of distance)??
If you are willing to pay for it, yes. Strictly speaking, the light composing the visible dot in a parallax-free optic is always parallel to the line of sight regardless of viewing position, whereas the light composing the dot in a non-parallax-free optic isn't parallel to the line of sight except at the exact center of the lens.

The two ways it is normally done are holography (Eotech) or a second, parallax-correcting lens behind the reflective surface (Aimpoint). Both approaches increase the cost of the sight, which is why cheap department-store red dots aren't parallax corrected but $300-$400 optics are.

svtruth
May 2, 2011, 05:10 PM
I'll say no. Unless you had a weird round with a tunnel through it. The sights will always be displaced from the bore axis. Imagine trying to hit a target 1" in front of the muzzle. But as someone noted earlier, bullet drop is a way bigger issue.

Kurt_D
May 3, 2011, 01:48 AM
I'll say no. Unless you had a weird round with a tunnel through it. The sights will always be displaced from the bore axis. Imagine trying to hit a target 1" in front of the muzzle. But as someone noted earlier, bullet drop is a way bigger issue.

Height over bore and bullet drop have nothing to do with parallax. 0 parallax means the dot stays on the poi no matter where you head is. It's already been explained how EOtech (parallax free) and Aimpoint (100% parallax free pass 25m) do it. Bullet drop and height over bore are always factors and are remedied by zeroing, hold over/under, a ballistic rectical, and/or by straight up adjusting the optic.

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