Eyeglasses.

[Starre]

You got it - tang sights did apertures first. The US Military adopted peep sights developed by Lt. Col (later General) Adelbert Rinaldo Buffington in the 1880's, and the Springfield trapdoor was the first US Rifle issued with the Buffington sight. This sight design was later carried to the 1903 and 1917, and heralded the development of the aperture sights used on the M1 Garand, 'the greatest battle implement ever devised'. Beyond hyperbole, the M1 aperture sight gave our troops a huge advantage over the Mauser or the Arisaka, which still had V-notch sights. The benefit to your eye's depth of field with an aperture is huge in accuracy.

 

[Mike in FL]

I tried the 1.25 drugstore glasses this week.Much. better shooting.

 

[Starre]

What are you shooting with the 1.25? Buckhorns? If so, how is the balance between focus on the sights, versus focus on the target?

If you increase power to a +1.50, the sights will get sharper, but the target gets fuzzier. If you decrease power to a +1.00, the target gets sharper and the sights get fuzzier. Without having measured distance from my eye to the rear sight of a rifle, I estimate that the ideal power is somewhere around 1.00 to 1.25, so you might very well be ideally set up with 1.25.

 

[Mike in FL]

Yes sir, 1.25 works well with buckhorn rear and brass blade up front. I am considering a prescription that focuses midway between front and rear. You are right; up close magnification blurs the target, but not by much.

 

[nhmoose]

If you want to advertise your service and business here Maby, you should become a sponsor first but that's MHO.

I most likely have more time [Hours and days and years} at MIT and Harvard than you have. Did not get degrees but revenge on rainy nights. Pluss many arrests and convictions.

Pay to play IMHO

Great post otherwise.

 

[LME]

I'm new to muzzleloading - actually, I don't even do muzzle loading. I'm a Service Rifle shooter, retired mechanical engineer who studied optics at MIT, photographer, and I'm old enough my near vision went, so I studied the optics of the human eye and developed the solution for shooters. I have been doing corrective lenses for shooters for 10 years, and was recently told at Camp Perry that I need to talk to the muzzle loading community, especially since I live in Cincinnati, right next to Friendship. So ...

Definition 1: Depth of Field (DoF). Your eye only has one theoretical focal point at any particular moment, however if the width of the blur line of an 'out of focus' object is smaller than the distance between two photoreceptors on your retina, you cannot see it. Hence the theoretical focal 'point' is actually a range including some distances closer than the focal point, and some distances further than the focal point. How big your DoF is, is determined by the size of the aperture you are looking through.


Definition 2: Aperture. The smallest opening in your optical path. Within reason, does not matter where it is. It might be your pupil, it might be an aperture sight on the rifle, or it could be a sticker with a small hole drilled in it that you have stuck onto your eyeglasses, or a merit disk. When people find that they can focus better with more light, it is not actually because of the increased light, it is because the increased light makes the pupil in your eye constrict, reducing aperture size, improving your eye's natural depth of field.

Definition 3: Diopter. A measure of lens strength, based on how much it shifts your focal point. The relaxed (or corrected) human eye focuses at infinity. If you add a positive diopter lens, it will shift your focal point closer without your eye making an effort. The adjusted focal point will be the inverse of the diopter strength, in meters. eg, if you add +2.00 diopters (typical reading glasses strength), your relaxed eye will be focused at 1/2 meter, about 20", good arm length for reading. Some people prefer +2.50 diopters, 1/2.5 = 40 cm = 16". +3.0 diopters is 1/3 meter which, if you remember the old 12" rulers that were 30cm on the other side. Reciprocals work too: +0.50 diopters = 1/2 diopter = 2 meter = 8 feet. These are awesome for watching television. The human eye can detect changes in focus about as small as 1/8 diopter = 0.125. So basically, from +0.125 = 8 meters, out to 0 diopters = 1/0 = infinity meters, it all looks the same. So basically, all targets are at optical infinity.


A sight picture needs two things: for your eye to have a good depth of field, and your point of focus must be at a distance so the depth of field is centered between your sights and the target (referred to as the hyperfocal distance in photography). Ideally, your depth of field is big enough that the sights are in the near edge of your depth of field, at the same time as your target is in the far edge of your depth of field. This part of my theory is a departure from the old adage 'focus on the front sight'. It might be OK to concentrate on the front sight, but if you truly focus ON the front sight, your target is too blurry. By focusing at the hyperfocal, you have slight blur on the target, and slight blur on the sight, but the clarity looks balanced.


As stated, the relaxed (or corrected) human eye focuses at infinity. You exert the ciliary muscle in your eye to squeeze the lens, which brings your focal point closer. You relax the muscle, and the lens' elasticity restores focus to infinity. At around age 40, the lens loses it's elasticity, and the muscle has to struggle harder to focus up close. For really close, you cannot do it, for medium close, you can do it for a few seconds, and the muscle tires and fades. Another way to bring your focus in closer is to add a positive diopter lens in front of your eye, aka reading glasses or a bifocal if you have distance correction. Lens power relates to focal distance, however standard reading glasses are typically MUCH too strong to shoot with.

Seeing the front sight is a 'middle distance' where shooters struggle. With a rear aperture, the correct answer on a rifle is to add +0.50 diopters of lens, because you are balancing focus between front sight and target, leaving the aperture fuzzy. This is way weaker than reading glasses. With pistol, where the sights are closer, you want to add +0.75 to +1.00 (depending on how blurry you like the target). I have never experimented with buckhorn sights, but imagine it will be at least +1.00 if you want to balance focus between the rear sight and the target. If someone can tell me the distance from your eye to the buckhorn, I can run the math and give a quick estimate.

Bottom line, to see your sights like you did when you were 18, you need to use a +0.50 lens, and an aperture sight. If you shoot buckhorns, you likely need a +1.00 lens, and put a sticker with a small hole on your glasses (like eye pal, or make it yourself).

Art Neergaard
ShootingSight llc
www.shootingsight.com

When my eyes started going south on me my accuracy started to follow. To solve this problem I started burying the front sight as deep as possible in my rear sight which helped some but not enough. I played around with some weird ideas to improve my accuracy hopeing I could begin to shoot like I use to? What I found was a revelation. What I did was polish the post on my M/L and put a light behind me making sure the light didn;t shine on the rear sight only the post sight. This helped me since all I had to do was bury the post and watch the glint off the post. I didn;t need to focus so much as the glint from the light was all I could see. When the glint of the light started to flicker in the receiver I fired. I have shot at a 100 yards using this method .I have even shot groups of three shots that were all touching. This was all done at the bench not off hand. The only problem if you can call it that is your group are going to be low and you will have to adjust for it.

 

[barracudadave67]

SO............You guys that shoot with a rear peep sight............. What is a good diameter, for the arpeture,??

I have been experimenting with them on my CW Muskets, and am thinking of drilling it out bigger. At present i have an arpeture of .072 inch. I am thinking of taking it out to .090 inch.

What sizes are you guys using,???.

Thanks
Dave

 

[Starre]

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[Starre]

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[Johnny Tremain]

I just moved my rear sight forward. A lot cheaper than eye wear