I've copied this over from the AZ board...this is obviously a better location for this topic
Some history first...
Before volunteering as an IIT, a friend of mine and I signed up for a shoot in Buckeye, AZ late last year in 2014. Actually of couple of shoots. We got our patches and were shooting semi-auto with rifle scope at the time. Well, at the next shoot we signed up for, Seth qualified with a bolt action w/riflescope. Hmmm, how to beat that? So I recently got myself a CZ455, bolt action w/iron sights!!!
And this is where I eventually had my 'ah ha' moment while practicing with the new rifle at the Ben Avery Range in Phoenix, AZ.
We've probably by now all read the story on this forum about the old guy that qualified Rifleman even though he could not clearly see the target. He just put the front sight on the fuzzy target....the rest is history.
Here's what happened to me...
I used to have 20/20 vision....before I was interested in shooting, so I can only fantasize about how good I could have been in my youth. Then some years later I needed glasses for distance, but I was still able to resolve both near and far with my new glasses (no bifocals). More recently in the past 1-2 years, my near vision has now somehow gotten a little better (the eye doc says that's normal for some old guys...) but I still need glasses for distance. So now when I'm behind the rifle looking down the iron sights WITH my glasses on, the front looks OK, not perfect but OK, while the target is nice and crisp.
To test accuracy on the new rifle I FIRST but a scope on it and at 25 yds was mostly able to drop 5 into one of our sighter squares. I was happy with my new purchase!!!
Over the next 3 weeks at Ben Avery I then removed the scope and just shot with the iron sights that came on the rifle; a hooded front blade and a shallow rear v-shaped sight...mounted forward of the bolt at about mid-barrel!!! What a disaster!!! I was getting really frustrated. Groups? There were no groups!!! I was all over the place. But, every once in awhile I was getting a semblance of a group onto the sighter square, so I figured I must be doing something right every once in awhile, but what was it???
On the 3rd week at the range it was really hot that day (~106F). While shooting a string of 5 at the sighter square, my glasses slid off my nose and dropped down enough so that I was looking at the front sight with just my eyes and no glasses....so that's what the front sight is supposed to look like!! Man was it clear and crisp. LIGHTBULB MOMENT!!!
I had been using those same shooting glasses for soooo long that I never even realized that the front sight was actually a bit fuzzy; I had no comparison...until I saw the front sight without the glasses.
So for the past two weeks at the range I've been shooting with uncorrected safety glasses. It's still a bit weird. It will definitely take some getting used to. Now the front sight is crispy as all getup, but of course the target is barely visible. Due to the contrast of black on white for the sighters I have a good 'sense' of where the target is. The target has absolutely no definitive edges...it's just a semi-grey blob, barely visible, sitting under my front sight. Also, since the front sight covers the square at this distance, I only barely see the target at the TOP of my breathing cycle since at the bottom of the cycle I'm fully on target and the sight covers the target.
The silver lining is that since the target is now so fuzzy, trying to focus on the target actually makes my eyes hurt...so I don't do that!
But, now about 60% of the time, I group 5 into a square. Most times, I still don't have that same good, confident feeling shooting at a fuzzy target that I did when I was shooting at a clear, crisp target. But, this is all on a controlled range and I'm only trying to get better using irons. And my friend Seth, well according to him his eyes are so bad that he can't even see at all a fuzzy target without correction. So when I shoot Rifleman with a bolt action w/iron sights, unless he pulls out the bow and arrow.....
In my defense, my problem isn't that the target is fuzzy at 1x. The problem is that the 300m and 400m targets are one big fuzzy blob at 1x. :)
I'm waiting on a new set of glasses, though, so we'll soon see if my eye dr. has gotten things dialed in for me. You know, at the KD shoot that you won't be attending. :) :) :)
If someone is saying or implying that a clear target is more important than a clear front sight, they don't understand much about rifle marksmanship. I have told the story of the 50 something guy with the fuzzy target many times because I was there. I know that story has been told in NJ, OH, NC, VA, SC, GA, AL, MO, IN, WV, and PA by me. It was also told many times in more states by VAShooter who was also there. And I imagine that other instructors may have seen or heard the same thing, but the event that I refer to happened in VA in 2008.
A fuzzy target is not an issue with irons. But with a scope you want clear distance vision.
With an AR, the correction for most people for a good front sight and an acceptable target is +.75 diopters over their normal distance correction. If the +.75 puts you within +- .25 of 0 you can have an ok front sight without any correction.
Mike
As you've both obviously figured out, in order to shoot well with iron sights the front sight MUST be in focus. As close to crystal clear as you can get - those of us with an astigmatism know it's not always possible to get a CRYSTAL clear front sight - but the closer you can come to a clear front sight, the better you'll shoot.
It's absolutely okay if the target is blurry, but the best possible scenario is a clear front sight and a slightly fuzzy target. Most of us with healthy eyes can achieve that, but it isn't always obvious how to do that.
The first thing to understand is how apertures work. The small hole in the aperture essentially filters out "stray" light rays, and dramatically increases your depth of field. All photographers have learned this as they learned how to take pictures. A small aperture gives you a large depth of field, and a wide aperture gives you a very narrow depth of field (the range at which everything is in focus). So the smallest aperture that still gives you "enough" light is almost always the best way to go (and aperture sights are always going to give you a much better sight picture than notch and post sights). How small you can go depends on your eyes and the conditions that day, but most shooters do best with an aperture in the range of 0.040" to 0.050" (depending a bit on the rifle and how close your eye is to the aperture). As an aside, the standard aperture that comes with Tech Sights is far too large to give you the best sight picture in most cases, and I recommend the Tech Sights aperture kit (Insert Ready Aperture System) with the smallest (0.042") aperture insert.
The next important thing to understand if you want your best sight picture, is another concept photographers understand called hyperfocal distance. As we get older, our eyes can no longer easily adjust to focus on things up close (like rifle sights), a condition known as presbyopia. When we were younger, our eye would rapidly change the focal length of our lens to focus on things near and far - so quickly in fact that we never even knew it was happening, and we could see target, front sight, and rear sight all in focus. As we get older our eyes simply can't do this anymore, so we need lenses to help. Reading glasses and bifocals are of course the most common item we use to be able to see things up close, since our eyes can't do it on their own anymore.
For shooting purposes, what we want to do is take advantage of something called hyperfocal distance. I'll share the Wikipedia definition of what that is, then we'll discuss what it means to shooting:
QuoteThe hyperfocal distance is the closest distance at which a lens can be focused while keeping objects at infinity acceptably sharp. When the lens is focused at this distance, all objects at distances from half of the hyperfocal distance out to infinity will be acceptably sharp.
When we apply this focus to shooting, we want objects at infinity (the target) to be acceptably sharp, while also keeping the front sight acceptably sharp. In practical terms, we want our relaxed vision to be focused not at infinity (the target), and not at the front sight, but at a distance in between those. By focusing our vision on an imaginary spot (which turns out to be roughly twice the distance between our eye and the front sight), we can achieve maximum depth of field with an acceptably sharp target and front sight.
Unfortunately most eye doctors don't understand this stuff, and most shooters don't either, so it can be a difficult thing to understand and get help with. Good news is other shooters have already worked this stuff out, so it's really not so hard. Start with your standard distance prescription from your eye doctor. They are trained to give you as close to perfect infinity vision as they can, so we'll call this our infinity correction. In your case, Chimich, you said you needed glasses for distance, which tells us your natural focal plane is too close (so is mine), so the eye doctor gave you glasses with a negative diopter, which corrected the focal plane of your eyes to infinity.
When you tried to see the sights, though, you simply could not. Your eyes can no longer easily adjust their focus to see that close, and your distance prescription moved your focal plane all the way out to the target. Taking your glasses off, however, moved your focal plane closer to you, and the front sight was nice and crisp, with a very fuzzy target. If we tweak that situation just a bit, we can use hyperfocal distance to give you the best of both worlds (or somewhat close, at least).
In short, take your standard distance prescription, and add +0.50 to +0.75 diopters to it to get your hyperfocal distance. If you're shooting a rifle with a longer sight radius, like an M1 Garand, a +0.50 adjustment is usually ideal. A rifle with a shorter sight radius like an AR15 will usually need something more like a +0.75 diopter lens.
So for you, Chimich, if you know (or can find out) what your distance prescription is), you can easily calculate what it needs to be to shoot best with iron sights. In my case, for example, my shooting eye prescription is a -4.75 diopters (I'm very nearsighted, or myopic). When I shoot, I use my regular contact lenses with the -4.75 diopter correction, but I add a +0.75 diopter lens insight my AR15 sight hood, which gives me my hyperfocal distance correction, and allows me to see an acceptably sharp target and front sight.
Hope that makes sense, as vision is an important part of shooting with iron sights, and it can get very complicated!
Don't forget so spray a little "Sight Black" on that front sight. Its amazing (after you do the above lens corrections) how much crisper the sight becomes when any stray light reflections are eliminated. You won't believe it until you spray some on. Its inexpensive and easily wiped off after a day gratifying day of iron sight precision shooting has been achieved!
What I have found over years of shooting is (masking tape) light it on fire and smoke your front sight with it, it works well. And it is cheap. Everybody has an old roll kickin around the house somewhere, give it a try, that is all I've used for the last 30 yrs.
Probably due to the number of birthdays I've accumulated I can't even remember when was the last time I saw a clear front sight. Even though I attend CMP events, I do it as training for my hog hunting trips, but I like to abide by the rules (iron sights). I heard about a product called MISO sold by Creedmoor Sports. It's supposed to be CMP and High Power legal. Clarity of the front sight has returned. Other problems that remain are due to cataracts, but that is another story. It's pricey, but nowadays everything is. The optical principle behind it beyond my understanding, I like to call it PFM.
aj
Regarding the clarity of the target, one thing that works for me is to consider the center of the blur as the center of the target. Like jmdavis posted, you want a clear front sight, the degree of clarity of the target is not as important (to me), although I have to confess that I would like to see a clear front sight and a clear target (with iron sights). Mission impossible. But my method has proven more than adequate for MOH (minute of hog) accuracy.
aj
The MISO sight is very interesting, and works very well for some shooters. It is basically a very simple Fresnel lens, designed to focus on both the target and the front sight. I won't go into the nuts and bolts of HOW it does this unless you guys want me to, but it does work.
The key thing to remember with the MISO is that it only works if your corrected distance vision is fundamentally good. In practical terms this means your only significant vision challenge is presbyopia (can't focus up close, need reading glasses, etc). If you have other issues like astigmatism, cataracts, floaters, retinal detachment, etc it likely won't do much for you.
As far as I know they make them for AR type sights and for M14/M1 sights, so if you have something else they aren't really an option. I can tell you that before my astigmatism got worse I could see a 3" spotting disc at 600 yards through that lens. As my astigmatism worsened I quit using it as my sight picture was worse than using nothing.
My HUGE problem is that I had lasix surgery on my eyes (astigmatism) in 2004. Although I love the fact that I no longer have to wear coke bottle lenses and can see well enough to read road signs, drive, etc. without glasses, it's frustrating that my vision is double when looking at near objects, especially fine print or lines. Lo and behold, the crosshairs are fine lines so when I look through a scope, I have to choose one of the two sets of crosshairs I see, and stick with them.
I simply see the fuzzed out target as a 'backdrop'. Sort of like white noise from a TV that you can hear, but it's indistinct. You know the target is there, your mind is focused on it, but your eyes are 'tuned in' to the crosshairs. I have fun with that and enjoy challenging myself with my focal point eyesight difficulties.
While this may not be your problem, by far the most common cause of "double" crosshairs is not focusing the eyepiece properly. It's an easy thing to do, but also an easy thing to mess up.
Every scope I'm aware of has an eyepiece focus ring. The purpose of this ring is specifically to focus the reticle, NOT the target. This can be easier said than done though, sometimes. In general terms, point the scope at something neutral (a blank white wall, the sky, something that your eye cannot focus on) and adjust the eyepiece until the reticle is in perfect focus. The tricky part is that your eye will attempt to compensate for an out of focus reticle, so once your pretty close to being in focus, move away from the scope and let your eye relax. Look through it again and you should see a clearly focused reticle. If you don't, keep at it until you do. The goal here is to have the reticle in focus with a relaxed eye. If you're seeing a double image of the reticle, odds are the eyepiece focus needs to be adjusted.
Once this is done you can look at a target. If you have a fixed parallax scope the target will only be in perfect focus if your at the same distance the parallax is set for. This is rarely a problem at longer ranges but can be a big issue at 25m if you have a scope set for 100 yard parallax. If this is the case, you have little choice but to deal with it or get a scope with an adjustable objective. Attempting to improve the focus on the target with the eyepiece will only hurt things, as you're still dealing with parallax errors and in addition you've now added the issue of a blurry reticle. A scope with fixed parallax can only ever be in perfect focus at one distance.
If instead you have an adjustable objective (often called side focus) then once the reticle is focused using the eyepiece, use side focus or objective focus ring to bring the target into focus. There should be marks on the focus ring or knob that will get you pretty close and you can find tune from there. If done properly, you'll have a perfectly focused sight picture and you will have eliminated any possible parallax errors. Move your head side to side while looking through the scope at a target and you should not see the crosshairs move one bit. If they do, you're off by a bit on one of these focus steps and can adjust until you no longer see any movement in the reticle regardless of your eye position.
This is almost always explained in the scope manual that came with your scope, but it may be in Chinglish and most men don't read instructions anyway!
Emkay if your seeing double on close objects normally, then this may not solve your problem, but it may help. You may want to talk to an eye doctor about your specific issues, though as I understand it things like that are not real uncommon with lasic surgery.
Quote from: Agrivere on October 19, 2015, 08:56:54 PM
Emkay if your seeing double on close objects normally, then this may not solve your problem, but it may help. You may want to talk to an eye doctor about your specific issues, though as I understand it things like that are not real uncommon with lasic surgery.
And that's exactly the issue. I see double on close objects normally. I've been to the doctor. The one who did the surgery on my eyes has examined them many times since. (I have to go every 6 months to get them looked at). I notice when they dry out a tiny bit the ghosting/doubling is worse.
Long Eye Relief Scopes on a Scout style mount I have been told will help with the "close focus" lasik issue.
For those curious and interested shooters, the last issue of Shooting Sports USA has an article titled Right RX for Aging Eyes. Pretty much what has been said here, but interesting nevertheless. www.ssusa.org.
aj