Help with sighting suggestions

Good day, new here and new to bulls eye shooting.

I have very bad eyesight, over 20/200 in both eyes uncorrected. I also wear bi-focals. With a good adjustment to my prescription I still can only see one thing at a time. I can either see the sights or I can see the target, not both. I can get a good alignment, but have no idea where I'm aiming. Or, I can see the target, but can't get an alignment. I've checked out some suggestions with making the dominant eye lens for close up and the other for long distance. There are some other suggestions with the glasses set up as well. My problem is I do not have a dominant eye. I can only shoot with one eye open. I've practiced to have both open, but both are fighting for dominance and it throws the image off.

If you’re righty, try a blinder on your left eye. Leave left eye open and blinder will allow right eye to be your aiming eye. Simple as that!
You can use a piece of tape on your left lens as a blinder to start with.
Jon

Nobody can focus on the front sight and target at the same time. When the sight is sharp, can you see the target at all? Normally, we aim at either the center of the fuzzy black circle or just below it. If you can't see it at all, try an Eyepal or Gehman iris. They will improve your depth of field to sharpen the target.

You CAN see the target and the sight at the same time - it's called Depth of Field.  Do a search on my name if you want all the optical math, but here is your basic solution:

1.  Use a blinder that is translucent, rather than closing an eye.  If you use an opaque blinder or close an eye, the pupil in your open eye will dilate, robbing you of depth of field.  You need to let light in, but just fuzz the image.  A small spot of tape on your eyeglass lens will do it, or if you want to make a complete blinder, cut it out of a milk jug.
2.  See if you can use a reduced aperture on your aiming eye.  You can buy an Eye Pal, or you can email me at info@shootingsight.com and I'll email you a few free stickers I make out of aluminum foil with a 1/16" hole punched in them.  If you have a dedicated set of glasses for shooting, these are the best solution, if you have to put it on/off multiple times, the EyePal is a cling film plastic without adhesive.  Merit disks also work.  When I say 'see if you can use a reduced aperture', this is driven by the lighting in your range.  Well lit ranges you can get away with it, dim ranges you might find that the reduction of light from an aperture is problematic.  Outdoors is no problem.  The smaller the aperture you use, the bigger your depth of field.
3.  You want a lens that is +0.75 added to your distance prescription.  This will put your focus half way between your sights and your target, a distance that in photography is referred to as the hyperfocal distance of your sights, and it centers your depth of field between the sights and the target, so the sights fall in the near edge of your depth of field, while the target is in the far edge, so you can see them together.  If you use an aperture, some shooters feel that adding +0.75 leaves the target TOO sharp, so they prefer adding +1.00, which brings your depth of field a little closer to the sights and blurs the target slightly.

Shootingsight,
We CAN do a lot of things, but going down the rabbit hole if we CAN see the target and the sight at the same time………

Not to be an ass, but if I am I accept full responsibility. Don’t come on a BULLSEYE forum and start the we CAN……stick to the BULLSEYE fundamentals.

Sight alignment; front sight in focus, rear sight and target are blurry/fuzzy.

Depth of field; blah blah blah.

Am I an optometrist or ophthalmologist? Nope. The Focus IS on the front sight and the target and rear sight are not in focus! Period! I went Service Pistol Distinguished in four matches; 10, 10, 8, and 10 point legs. ALL focusing only on the front sight. Aim at the blur! All with 230 gr Hard Ball ammunition; especially with hard ball.If you not purely focused on the front sight you will never get off 5 perfect shots in a sustained fire string. Taking time to try and focus on the front sight and the target because depth of field allows me to do that is hogwash. Shooters whose focus bounces back and forth between the target and front sight will only shoot marksman level scores. Marksman is 85 and below. If you try and focus on more than the front sight it will be BELOW.

Reminds me of going to college. The professor told the class, “you can’t make up your own math”.

Stick to the fundamentals……..that’s why we teach and use them. It works!
Jon

I struggle with glancing between the pistol sights and target. Subconsciously, I think my eye gravitates toward the sharpest image in the milliseconds just before the gun goes off. I want that to be the front sight. Embarrassingly enough, my best 20 shot score at 50 yds remains one time when I completely blurred-out the target. I turned around the repair center and aimed at what I thought was the bottom of the aiming black. I figure that's no way to practice, since you can't compete that way, but it surprised me what happens when you limit yourself to a single point of attention. Now I just need to learn to let the gun fire without anticipating recoil and dropping the muzzle.

We had a previous extensive thread on just this topic.  To reinforce  Jon's advice, it takes time to adjust eye focus - longer as we age and upwards of several hundred millisec. If you are focusing back and forth, whether irons to target, dot to target - you are wasting precious time during sustained fire strings.

sharkdoctor wrote:We had a previous extensive thread on just this topic.  To reinforce  Jon's advice, it takes time to adjust eye focus - longer as we age and upwards of several hundred millisec. If you are focusing back and forth, whether irons to target, dot to target - you are wasting precious time during sustained fire strings.

  Is that why Photo Escape sells those aperture kits for red dots or is it to center the dot in the tube ?
Stan

chopper wrote:

sharkdoctor wrote:We had a previous extensive thread on just this topic.  To reinforce  Jon's advice, it takes time to adjust eye focus - longer as we age and upwards of several hundred millisec. If you are focusing back and forth, whether irons to target, dot to target - you are wasting precious time during sustained fire strings.

  Is that why Photo Escape sells those aperture kits for red dots or is it to center the dot in the tube ?
Stan

Stan, 
I found with the red ring on rear of optic I didn’t get the eye bounce as I call it. I could stay more easily focused on the red dot.
Dr. Norman Wong came up with the method originally using rubber bands.
Jon

I did the mechanical design on the R7 Streetview camera. None of the optics, but you learn a lot in the process.

There's no such thing as "Depth of Field". It's correctly referred to as "Apparent Depth of Field". As long as your eyeball can't tell it's out of focus, it appears to be. And so you make some determinations of what distance to set the focus at. I think I remember that it's not the center of your range limits. It's offset ... closer? ... to compensate for the non linearity.

Some cool stuff in that camera, rolling electronic shutters that swept around the cameras to reduce motion blur and have the images sync'd. One of the things I stumbled across was the AR coatings spec. The last one being 'Silicon Dioxide" ... wait, isn't that 'glass'? Yep, it's abrasion and water resistant to avoid scratching the lenses while cleaning them. BTW, some of the coatings on there *are* water soluble, so you gotta have something that isn't protecting them.

And that was nothing compared the last nightmare I was working on ... My friends refered to the support structure as my "Sheetmetal Taj Mahal".

I think the OP has an issue that perhaps some of the others miss.  And that is a psychological desire to “see the target” at least at some level of definition.  Needed? No! Wanted? Yes! So it would be my suggestion is to use a combination of an aperture to increase depth of field AND specialized prescription to move the eye correction to distance plus 1.0 diopter.  Any decent optometrist should be able to accommodate this.  Try and keep your focus solely on the front sight at 25 yards even if you have to open the aperture.

Thanks for the suggestions. I will try them out.

To clarify, my vision is very bad. It's not an issue of maintaining focus on the front sight. At 50' I can tell there is a target in front of me. At 25yds the target is a tan and black circle. I know to aim for the middle, can't make anything else out. At 50yds its just a blob blending into the background. This is while using the close focus of the bifocals to get a good sight alignment. If I focus on the target with the long vision part of the glasses (which I know not too) the target is clear, but the sights are just blurry posts with no defining edges.

Jon Eulette wrote:

chopper wrote:

sharkdoctor wrote:We had a previous extensive thread on just this topic.  To reinforce  Jon's advice, it takes time to adjust eye focus - longer as we age and upwards of several hundred millisec. If you are focusing back and forth, whether irons to target, dot to target - you are wasting precious time during sustained fire strings.

  Is that why Photo Escape sells those aperture kits for red dots or is it to center the dot in the tube ?
Stan

Stan, 
I found with the red ring on rear of optic I didn’t get the eye bounce as I call it. I could stay more easily focused on the red dot.
Dr. Norman Wong came up with the method originally using rubber bands.
Jon

This might be a long post, sorry!

Firstly - "Depth of Field" - this is valid term when it comes to photography.  And it has something to do with Aperture of the lens.  I do not want to write too big of an essay here on the subject.  Short version - smaller opening in the lens combined with longer shutter speed (need enough light to pass through) plus the third component, which is film or sensor sensitivity (commonly referred as ISO) provide for more objects at various distances being sufficiently sharp on pictures.  The gist here is that pictures are taken with static focus on particular subject (distance), which will be in the best focus, and other subjects at various distances will (shorter and longer) be sharp enough to thing they are in focus too, but they are not.  This approach would be very difficult to apply and use in shooting, - humans can't maintain same level of concentration on one subject for the same duration as photo camera can and get enough light through the pupil to see everything from 2' to 50Y.

Secondly - Depth of Field and Aperture have direct correlation to another term from photography - Field of View.  The smaller the aperture the lesser field of view camera can see.  In return objects in the Field of View are being in focus and seeing sharper (at specific distance).  That is where Aperture Rings idea comes from.  Combine this with Dr. Wong's RBR to keep eyes from wondering away from the dot, and you have visual aid to keep shooter's concentration on target and align dot with its center (concentricity and parallax in mind).  And it also helps to folks with astigmatism.  There are various devices use same concept - EyePal, Merrit, Champion Choice Glasses.  Difference with Aperture Rings is the distance from the pupil. 

Thirdly, and this is specifically for the OP.  As long as you see "a blob" representing center of the target, and can distinguish it from the rest of the target, you have something to work with.  This link might be very helpful - https://theweek.com/articles/473520/how-did-blind-archer-set-world-record-olympics.  Hitting bulls eye with bow and arrow at 70 meters (76.5Y)  isn't easier easier then shooting BE at 50Y.  Coincidentally Im Dong Hyun's vision was also 20/200, and he didn't wear any corrective glasses.

AP

Forget iron sights and shoot with a red dot.

Welcome to the club!

20/400 here. I wear progressive lenses daily and just can’t make them work for BE shooting. Ordered a selection of readers and landed on a pair that gave me good front sight focus. (As long as the lighting is good) Got thinking about it, and thought that a pair of bifocals might be the answer, and also help maintain a consistent head position. Wasn’t working for me, so back to the readers with an occluder on the non dominant eye. I find that the readers also eliminate trying to shift focus to the target.

I do the same for shooting with a dot, just a different pair of readers for that. 

Made a difference for me anyway!

Depth of field relates to the width of the blur line an object has that is not perfectly in focus.  The photo receptors in your retina have a certain size.  In the center of the retina the density averages about 150,000 receptors per mm^2, this works out to about 0.0025mm per receptor.  Since any perfect sharp edge will not likely illuminate one 'pixel' exactly 100% coverage, or 0% coverage, the eye cannot detect a noticeable blur line until the width of the blur is 2 pixels wide.  So 0.005mm of blur is the smallest a human eye can detect.  The human eye is about 20mm in diameter, and that calculates to about 0.9 MOA.  Indeed, the medical definition of 20/20 vision is to be able to distinguish 1MOA wide lines.  The eye chart in the optometrist's office is designed to have letters 5MOA x 5 MOA, so the letter E is made up of 3 black lines and two white lines that are each 1MOA wide.

So in a lens, there is only 1 perfect theoretical focal point, but there is a range both beyond the focal point and closer to the focal point where the blur is less than what can be seen, so your eye cannot see that it is out of focus.  There is an even bigger range where the blur is acceptably small, so the size of depth of field can vary depending on your definition of acceptable focus.  In film cameras, this depth of field was calculated based on the crystal size of the light sensitive chemicals, with the human eye it is cone spacing, but it is still there.

The width of the blur on an object is directly proportional to the diameter of the aperture - if you cut the aperture diameter in half, your blur line cuts in half.

In bullseye you want your sights as sharp as possible, and tolerate some amount of blur on the target.  The preference is for the front sight to be sharpest, allowing some blur on the target and some blur on the rear sight.  Getting even sharper on the rear sight is good.  Getting even sharper on the target is not always good, because beyond the definition of 'focus' is also the term 'concentration'  You want to concentrate on sight alignment.  If your target is too focused, it draws your concentration away from sight alignment.

So, getting back to my original recommendation: without an aperture, I recommend +0.75 diopters added to your distance vision.  This will center your depth of field between the rear sight and the target, so the rear sight and the target will have some blur, and your front sight, which is buried more deeply into your depth of field, will be sharper than your rear sight or the target.

If you use an aperture, it will sharpen the rear sight and the target.  As mentioned above, it might sharpen the target more than you want.  So the solution is to use a slightly stronger lens, a +1.00 which draws your depth of field slightly further back, sharpening your sights even more (good), and introducing slightly more blur into the target that was too sharp.

If you want to experiment with the recommendation that you should focus ON the front sight, you can try it.  Diopters are the inverse of focal length, in meters.  My 1911 has the rear sight about 24" from my eye, the front sight is about 6" beyond that, so front sight is 30" away.  THat is 0.76 meters.  So to focus my relaxed eye at 0.76 meters, I need a 1/0.76 diopter lens.  That would be 1.31 diopters.  You can get $5 reading glasses in either 1.25 or 1.50 diopters at the dollar store.  Get a pair and put them over your regular glasses/contacts, or alone if you have 20/20.  Form a sight picture.  What you will see is a BEAUTIFUL perfectly sharp front sight .... and your target will be so blurry you cannot see it.

You don't get to pick your own math, but since I studied optics as part of my engineering degree, and have a background in photography, and am a shooter, and have run a business for 15 years doing vision correction for shooters, I can assure you, this is THE math that optical physics is based on.

A-The aggressive tone is unnecessary
B-Please focus on the question asked. OP's vision, as described, is not average. It seems he asking for advice for his particular circumstance. I believe practical advice would be more helpful than a dissertation on optics.

Summary: Find lenses that help you see the front sight clearly. If the blurry target is discernable enough to aim at, you're golden. If not, some type of iris may help. Occluding the non-aiming eye with something translucent is best. Not closed, not black. I use scotch tape on the non-aiming lens.

Jon Eulette gave you sound advice by stating to shoot using the eye which corresponds to your dominant hand.  It's not a problem if you don't have a dominant eye. As stated by several responders, there is good reason to block off vision from the opposite eye so it won't interfere with the shooting eye, and several methods were recommended.

I don't believe you have "bad eyes" from what you described. The 20/200 level of vision is the "uncorrected vision" but as you stated, you see well far with the distance portion of your bifocals. The rule-of-thumb is that the visual acuity will drop one line for every 0.25 diopter of nearsightedness. Your 20/200 vision would then show about a -2.00D level for your distance prescription. Your age was not discussed but I would think that if the bullseye was totally blurred while looking through the bifocal segment, I would imagine your add would be in the range of +2.00 to +2.50D. This of course would definitely be awful in attempting to see your iron sights.

There are many suggestions as to where to have your shooting glasses focus when shooting with iron sights. I have written much about this subject but I won't bore everyone again with this topic. It's been discussed here already.

As you experiment, don't be swayed by what others insist would be best for you. From a comprehensive survey I did about 15 years ago among many of the top shooters in this country, the last shooter who won the National Matches with iron sights, did so by closing his eyelids of the non-shooting eye as he shot his rounds....... No occluder, no scotch tape, no flip down white or black occluder.

Norman H. Wong, O.D.

Based on the thin lens equation and some approximate eye sizes, I have plotted out the theoretical blur a human eye will see on the target, the front sight, and the rear sight, depending on the diopter added to your distance vision.  There are two ways to add diopter: either by adding a lens, or by exerting the eye muscle.  Generally, the less work the eye muscle has to do, the more consistent and stable your sight picture will be.

As you can see, at a little over +0.75 diopters, the blur on the target and the rear sight are about equal, and the blur on the front sight is relatively low.  In my experience, this is the power most shooters like if they are not using a reduced aperture.  If you use an aperture, the curves flatten out (though the crossover points do not change), and pistol shooters feel the target becomes too clear, so they will increase the diopter slightly to +1.00, improving sight focus, and restoring some blur on the target.

How much blur you want on the target is a personal preference, but a +1.25 add, which gives perfect focus on the front sight, generally gives too much blur on the target, unless you are shooting outdoors in bright light, with a very small aperture.

To put this all to practice, I got a 24mm lens for my Nikon camera.  The human eye is between 20 and 25mm in diameter, so a 24mm lens comes reasonably close to replicating the image that falls on the retina of the eye.  I have seen lots of photographs depicting a sight picture, but the photographer is trying to show an impression rather than replicate reality, so effects are exaggerated.

I put a 1911 in front of the camera with the rear sight 24" from the lens - about my arm's length.  I hung a silhouette target 50 feet away.  I set the aperture to a 1/4" opening, similar to a human pupil indoors, so depth of field is comparable to the eye.

I took pictures with the focus set to diopter equivalents of zero to +1.50 Added.

Images are a little grainy, because the sensor on the camera has a pixel density that is about half that of a human retina, but you can still see the effect - if you add zero diopters, you are effectively focusing on the target and your sights are too blurry.  As you add more power the sights come into focus and the target starts to blur.  Around +0.75 your front sight is are reasonably sharp and the target is fuzzy, but still visible.  Up into the +1.00 to +1.25 range the sights are fantastic, but the target is now washed out.

This is a +1.00 diopter with a 1/8" aperture.  Target blur is similar to the +0.75 lens with no aperture, but the sights are much sharper.  Downside is that this aperture only lets in 1/4 the amount of light.  In a camera I can offset that by adjusting exposure, but the eye cannot do the same thing.  So if you are in a dim range, reducing aperture is not always an option.

Nice pictures, but they don’t represent how we actually see our sight pictures.

Norman

My images represent a spectrum from 100% focus on target to 100% focus on sights.  Where do you see your sight picture in that spectrum?

I think we are all in agreement that the best sight picture requires some amount of positive diopter be added.  I think all data says that it is more than 0.25, and less than 1.25.

What, in your experience, is the typically preferred added power between 0.25 and 1.25?

I understand what the illustrations are attempting to show but the blurred images of the targets or sights are overly exemplified. Does anyone else see this?

xmastershooter wrote:I understand what the illustrations are attempting to show but the blurred images of the targets or sights are overly exemplified. Does anyone else see this?

To my eye (wearing corrective toric contact lenses and wearing different +magnification safety glasses), the targets (black) in SS's chart of images and diopters look representative of what I see at those powers at 50 ft with my own +0.5 and +0.75. My front post though at +0.5 looks like his +1.00 (I can barely tell that I can't see it perfectly) and my +0.75 closer to his +1.25 front post. I've never noticed my rear sights being quite that blurry at these powers also. I really appreciate the chart though.