Hi all,
I came across this interesting product http://www.shootingsight.com/ . This is an rectangular aperture in which they claim will give you better focus on the horizontal. I shoot high power with 6 o'clock hold and sometimes the bull can get very blurry so I am very much interested in this product, but don't want to spend the $80 for the sight just to experiment.
Please let me know if anyone has any experience or knowledge of this, thank you.
David
Rectangular Apertures
Moderators: pilkguns, m1963, David Levene, Spencer, Richard H
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westerngriz
I think that "optics are optics" and what works for a camera will be the same that works for your eyes.
Camera manufacturers have always strove to make the adjustable iris as round as possible. Additionally when fixed apertures are used they are always round.
The other factor (that is often overlooked) is that the aperture should be as thin as possible to reduce refraction at the edges.
In any case you can run a cheap at-home test to check on this. Get some black construction paper and a hole puncher and an utility knife.
Punch a hole (round) and cut a rectangle and hold it up to your eye and compare. While you are at it cut a narrow slit and see what that does.
Do the experiment and report.
Regards,
Packard
Camera manufacturers have always strove to make the adjustable iris as round as possible. Additionally when fixed apertures are used they are always round.
The other factor (that is often overlooked) is that the aperture should be as thin as possible to reduce refraction at the edges.
In any case you can run a cheap at-home test to check on this. Get some black construction paper and a hole puncher and an utility knife.
Punch a hole (round) and cut a rectangle and hold it up to your eye and compare. While you are at it cut a narrow slit and see what that does.
Do the experiment and report.
Regards,
Packard
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westerngriz
Here is their website. I don't know exactly what he was referring to.Leo wrote:Matt -- what is the reference to "b. jones"? Thanks...
http://www.bjonessights.com/
Thanks all for the info.
Matt, thanks for letting me know that this is not legal for CMP as I am shooting the EIC matches and didn't think to ask if this was legal for such events. I noticed over the weekend that if I had used a amethyst filter, it does cut down a lot of fuzz that this aperture is suppose to get rid of. I am glad I didn't end up spending $80+ just to try out these sights!
Matt, thanks for letting me know that this is not legal for CMP as I am shooting the EIC matches and didn't think to ask if this was legal for such events. I noticed over the weekend that if I had used a amethyst filter, it does cut down a lot of fuzz that this aperture is suppose to get rid of. I am glad I didn't end up spending $80+ just to try out these sights!
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Guest
info on rectangular sight
David (and all),
I am not affiliated with Shootingsight LLC but am familiar with his product.
The rectangular rear aperture is designed for the AR service rifle with a post front sight. It is specifically designed to optimize your focus on the top edge of the front sight while still letting through as much light as a corresponding round aperture.
Many shooters, especially shooters over 40 years old, have difficulty focusing on the top edge of the AR's front sight post because of the very short sight radius. The theory behind this rectangular aperture is that the rectangular aperture's smaller vertical diameter can reduce the blur of the horizontal top edge of the front sight post, compared to a round aperture with the same cross-sectional area.
It is my understanding that the rectangular aperture is legal under NRA rules for service rifle, but not allowed under CMP rules.
I also understand that Mr. Neergard of Shootingsight LLC has a different type of rear aperture with some of the same features, but is CMP-legal. It is not described on his web sight, so you would have to call him for details.
Hope this helps. I am not affiliated with Mr. Neergard in any way, but he is quite knowledgeable about optical physics and is willing to explain this to others.
Randy
I am not affiliated with Shootingsight LLC but am familiar with his product.
The rectangular rear aperture is designed for the AR service rifle with a post front sight. It is specifically designed to optimize your focus on the top edge of the front sight while still letting through as much light as a corresponding round aperture.
Many shooters, especially shooters over 40 years old, have difficulty focusing on the top edge of the AR's front sight post because of the very short sight radius. The theory behind this rectangular aperture is that the rectangular aperture's smaller vertical diameter can reduce the blur of the horizontal top edge of the front sight post, compared to a round aperture with the same cross-sectional area.
It is my understanding that the rectangular aperture is legal under NRA rules for service rifle, but not allowed under CMP rules.
I also understand that Mr. Neergard of Shootingsight LLC has a different type of rear aperture with some of the same features, but is CMP-legal. It is not described on his web sight, so you would have to call him for details.
Hope this helps. I am not affiliated with Mr. Neergard in any way, but he is quite knowledgeable about optical physics and is willing to explain this to others.
Randy
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ShootingSight
Gentlemen,
My name is Art Neergaard, owner of ShootingSight and the rectangular apertures. Someone just alerted me to this discussion, so I thought it would be good for me to answer some of your questions 'from the horse's mouth" as it were.
Some background on what apertures do: First off, as you decrease opening size in an aperture, you improve depth of field in the axis perpendicular to the aperture opening. In other words, a horizontal line can blur up/down on the retina based on how tall the aperture is, and a vertical line can blur sideways based on how wide the aperture is. Secondly, the total open area of an aperture determines how much light gets through.
In shooting with a front post, focus on the horizontal edges is more important that focus on vertical edges because elevation aiming and windage aiming are two different things for the eye. Windage is an exercise in symetry. You have two vertical edges to the front sight post, and you are centering the bull between them. If the two vertical edges are crisp or fuzzy does not matter. You are still centering the bull between them. Elevation however requires crisp focus to tell when the bull is touching the post, because you do not have the symmetry of an inverted post above the bull. Hence. for a post shooter, horizontal edge focus is more important than vertical edge focus.
My rectangular apertures are small in the vertical direction, so the horizontal edge of the post cannot blur vertically on the retina, but to preserve overall image brightness (requiring the same open area), I need to make my width bigger, to compensate for the smaller vertical. hence, rectangular. Same area as the round opening, just redistributed. This is literally robbing Peter to pay Paul, as I steal some vertical focus to improve horizontal focus, without giving up brightness.
Some corrections: this helps with the post and the target. When someone heard it helps only with the post, what I meant to tell them is it only helps with a post sight. It does not help for a match sight, where the front ring has symetrical edges horizontally and vertically.
Further, it is NRA legal. The rectangular version is not CMP legal, since they changed their rules to require a round aperture. I do have a new design that uses a round aperture, and inclines the round opening to your eye, so even though it is a round hole in the plate, it appears slit shaped, It actually works better than the rectangles. I cannot say that this is CMP legal, as I have not asked them, though the CMP rules specifically say "round aperture", and the apertures in my sights are round. I'm up front with customers as to what the rules say,and how I am getting around them. So far, over 90% of customers get a good chuckle, and agree that they meet the letter of the law.
As to trying them, I offer 100% money back guarantee for any reason. If you try these and don't like them, I offer full money back.
If anyone want to call to discuss these further, my cel is 513-702-4879.
I can say that I count among my satisfied customers a double distinguished shooter, as well as a P100 shooter, who both believe they work.
Art Neergaard
ShootingSight LLC
www.shootingsight.com
My name is Art Neergaard, owner of ShootingSight and the rectangular apertures. Someone just alerted me to this discussion, so I thought it would be good for me to answer some of your questions 'from the horse's mouth" as it were.
Some background on what apertures do: First off, as you decrease opening size in an aperture, you improve depth of field in the axis perpendicular to the aperture opening. In other words, a horizontal line can blur up/down on the retina based on how tall the aperture is, and a vertical line can blur sideways based on how wide the aperture is. Secondly, the total open area of an aperture determines how much light gets through.
In shooting with a front post, focus on the horizontal edges is more important that focus on vertical edges because elevation aiming and windage aiming are two different things for the eye. Windage is an exercise in symetry. You have two vertical edges to the front sight post, and you are centering the bull between them. If the two vertical edges are crisp or fuzzy does not matter. You are still centering the bull between them. Elevation however requires crisp focus to tell when the bull is touching the post, because you do not have the symmetry of an inverted post above the bull. Hence. for a post shooter, horizontal edge focus is more important than vertical edge focus.
My rectangular apertures are small in the vertical direction, so the horizontal edge of the post cannot blur vertically on the retina, but to preserve overall image brightness (requiring the same open area), I need to make my width bigger, to compensate for the smaller vertical. hence, rectangular. Same area as the round opening, just redistributed. This is literally robbing Peter to pay Paul, as I steal some vertical focus to improve horizontal focus, without giving up brightness.
Some corrections: this helps with the post and the target. When someone heard it helps only with the post, what I meant to tell them is it only helps with a post sight. It does not help for a match sight, where the front ring has symetrical edges horizontally and vertically.
Further, it is NRA legal. The rectangular version is not CMP legal, since they changed their rules to require a round aperture. I do have a new design that uses a round aperture, and inclines the round opening to your eye, so even though it is a round hole in the plate, it appears slit shaped, It actually works better than the rectangles. I cannot say that this is CMP legal, as I have not asked them, though the CMP rules specifically say "round aperture", and the apertures in my sights are round. I'm up front with customers as to what the rules say,and how I am getting around them. So far, over 90% of customers get a good chuckle, and agree that they meet the letter of the law.
As to trying them, I offer 100% money back guarantee for any reason. If you try these and don't like them, I offer full money back.
If anyone want to call to discuss these further, my cel is 513-702-4879.
I can say that I count among my satisfied customers a double distinguished shooter, as well as a P100 shooter, who both believe they work.
Art Neergaard
ShootingSight LLC
www.shootingsight.com
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ShootingSight
A few further clarifications regarding Mr. Packard's notes (above).
Shooting a front post differs from photography, as photography has no particular need to bias depth of field in one axis or the other. A post shooter does. Other applications where people use a slit to their advantage is opthalmagists, where slits were used to give a depth of field advantage in one axis in order to diagnose astigmatism, so there is medical data to support that this works, just in a different aaplication.
As to an easy home example to see if this works, get a pair of calipers, and set the jaws so they are about 0.025" apart, then hold the jaws up to your eye as if they were a rear aperture (maybe 1"-2" away from the eye), then stick a vertical finger out in front of you at arm's length, as if it were a front sight. What you will see is that the blur line on the top of your finger is noticably smaller than the blur you see on the side of your finger.
If you want to try it with paper, use two pieces, and tape them together so two straight edges are not quite butted together, but have just a little gap, this will do the same thing. As you rotate the slit in front of your eye, you will see degrees of focus in different axes change.
By the way, your brain already knows this works. When you can't quite focus on something, what do you do? You squint. Here, your round pupil is being occluded top and bottom by your eye lids, creating a rectangular opening to your eye, and creating a horizontal bias in your focus. My aperture is just squinting for you.
As another aside, this is why cats and snakes have slit shaped pupils. Vertical pupils will primarily emphasize focus on vertical edges, since they live in a world of stems and leaves of grass.
Art
Shooting a front post differs from photography, as photography has no particular need to bias depth of field in one axis or the other. A post shooter does. Other applications where people use a slit to their advantage is opthalmagists, where slits were used to give a depth of field advantage in one axis in order to diagnose astigmatism, so there is medical data to support that this works, just in a different aaplication.
As to an easy home example to see if this works, get a pair of calipers, and set the jaws so they are about 0.025" apart, then hold the jaws up to your eye as if they were a rear aperture (maybe 1"-2" away from the eye), then stick a vertical finger out in front of you at arm's length, as if it were a front sight. What you will see is that the blur line on the top of your finger is noticably smaller than the blur you see on the side of your finger.
If you want to try it with paper, use two pieces, and tape them together so two straight edges are not quite butted together, but have just a little gap, this will do the same thing. As you rotate the slit in front of your eye, you will see degrees of focus in different axes change.
By the way, your brain already knows this works. When you can't quite focus on something, what do you do? You squint. Here, your round pupil is being occluded top and bottom by your eye lids, creating a rectangular opening to your eye, and creating a horizontal bias in your focus. My aperture is just squinting for you.
As another aside, this is why cats and snakes have slit shaped pupils. Vertical pupils will primarily emphasize focus on vertical edges, since they live in a world of stems and leaves of grass.
Art