Dear fellow AR enthusiasts,

The point of this thread is not to imply which scope is a better overall scope, but rather, to bring to light the parallax errors of both scopes.  I don't want to add more fuel to the ongoing fire of whether brand A is better than brand B.  After using the Search feature, I couldn't find one single post comparing the parallax errors between the Aimpoint and EoTech sights.  

According to both Eotech and Aimpoint, both of their sights are "parallax free".  But according to from what I have read from various sources on the internet, both sights do have some parallax errors.  I'd like to compare those parallax errors on this thread.  So, I'm posting what info I have found here, in hopes that you all can help fill in the gaps.

I will continue to update the following as more information comes to light.
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Eotech Parallax Error Specs: 1.3" @10yrds, decreasing as distances becomes further.  Almost 0 parallax at 50 yards.  Parallax free at 100+ yards.

Aimpoint Parallax Error Specs:  Parallax free while look through the scope at 100+ yards, since the 4moa dot (4.188" at 100 yards) is larger than the 3moa (3.141" at 100 yards).  
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Does anyone have any additional documentation from a reputable source, such as an Aimpoint rep, that describing any details of parallax errors? Lets not talk about realistic vs. nonrealistic shooting distances, lets just aim for the facts/specs.  Is it true that all red dots have some sort of parallax, even if it's 1" away from the lense?  


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EoTech Documentation:
According to the thread here: www.ar15.com/forums/topic.html?b=3&f=18&t=175640 Yojimbo provided us with a memo from a rep from EoTech that includes the following quote:

*** Chris, I don't belong to the chat group. I do not know how to reply to the group. You can pass along the information: What I read in the chat was someone looking across the room for parallax. At this close distance you will notice parallax. The sights do have parallax error of +/- 1.2 " or +/- 0.6" (1.2 " side to side). The sight is designed to be parallax free at long distance 100yds to infinity. At close range, there will be a parallax error equaling to the width of the window which is 33mm or 1.3". A perfectly aligned sight will have parallax error of 1.3" at 10 yds and at 17 ft. As you move further away from 10 to 40 yards parallax becomes less and is almost zero at 50 yards. If the sight is parallax free at 10 yds or 17 ft, it would be way out of alignment. Best regards, Greg Schultz, EOTech Customer Service 3600 Green Court, Suite 400 Ann Arbor, MI 48105 Ph:(734) 741-8868 Fax (734) 741-8221 WWW.eotech-inc.com

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Once again, this thread is not meant to weigh the advantages or disadvantages of either scope, since that is extremely subjective.  Rather, this thread is simply to gather data regarding the parallax errors of both scopes.


-Jim

Edited to add:  I don't claim to know anymore than anyone else, I don't claim to be able to do anything better than anything else, I am not selling anything, and I'm not trying to convince anyone of anything.  I'm just looking for facts.

[url]http://www.army-technology.com/contractors/machine_guns/aimpoint/[/url]

+++++++++++++++++++++++++++++++++++++
COMP M/ML SPECIFICATIONS - OPTICAL SYSTEM
Operating principle - Passive Red Dot Collimator Reflex Sight
Optical magnification - 1x, with unlimited eye relief
Clear aperture - 26 mm
Aiming dot size - 3 MOA, (0.9 mRad) nominal
[b]Parallax error, center < 0.75 MOA (0.2 mRad) within a 3.5 mm radius from center
Parallax error, overall < 3 MOA, (0.9 mRad)[/b]
Azimuth and elevation adj. > +/- 30 MOA (9 mRad) in 0.5 MOA (0.15 mRad) step
Dot brightness (M) 10 settings - Off, NVD (2), daylight (6) extra bright (1)
Dot brightness (ML) 10 settings - off, daylight (8) extra bright (1)
Dot color - Red (630-650 nm wavelength)
Optical coating - Anti-reflex, 1st, 2nd and 3rd generation NVD compatible (M only)
Optical signature - No forward optical signature from the dot beyond 10 meters
++++++++++++++++++++++++++++++++++++

What does this mean?

Dang, Jim I was just gearing up to do a post exactly like this one![:D]

Barring an addtion of a manual parallax adjustment, like on the high end magnified optics, it's starting look like there is no such thing a 100% parallax free.   It looks like optics can be dialed in to be parallax free from certain distances but it's impossible to have an optic be parallax free at all distances.

It does appear that both EOTech and Aimpoint have some degree of parallax issues at very close ranges.  I'm not sure how much difference it really makes but it's good to know.

The truth is out there...[:)]

Hey Yojimbo.  Had I known you were going to do this, I would not have posted this thread :)  It's all good though, we are both searching for facts.

Remember this spec, which actually comes from Aimpoint:


According to the 2nd Parallax error rating, I assume it's saying that there is a  parallax error of no greater than 3 MOA.  1 MOA = 1.047 inch @ 100 yards, so less than 3 MOA would mean less than 3.141" at 100 yards.  But since the Aimpoint dot is 4MOA, it should cover 4.188" at 100 yards.  [b]So, the Aimpoint is actually free of Parallax from the average eye at 100 yards, since the 4moa dot covers more than the Parallax error would account for at that distance[/b]

I still have yet to figure out what the first line means.

In addition, I found the following bit of information from [url]http://groups.msn.com/TheMarylandAR15ShootersSite/aimointm68zeroingmethod.msnw[/url]




-Jim

[b]Parallax error, center < 0.75 MOA (0.2 mRad) within a 3.5 mm radius from center
Parallax error, overall < 3 MOA, (0.9 mRad)[/b]

I believe what this is saying is with the dot in the middle of the sight window, within 3.5mm from the center of the sight window, there is going to be up to 0.75MOA of parallax error.

At the extreme edges of the window there is going to be up to 3MOA of parallax error.

There are 360 degrees in a circle and 60 minutes in a degree, so 21,600minutes per circle
There are 6.283 radians in a circle (2 pi) and milli=1/1000, so 6283 mRad in a circle

What they don’t tell us is at what distance does this affect the sight.

Is it like what EOTech claims and insignificant past 50 yards, decreasing linearly from max to nill, from muzzle to 50 yards respectively? Or is it constant to infinity, though I doubt it?

At 10 yards, 3MOA is 0.31” & 0.75MOA is 0.08”
At 100 yards, 3MOA is 3.1” & 0.75MOA is 0.8”

In any case the error is smaller than the dot according to this info.