Pennsylvania Firearm Owners Association
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  1. #1
    Join Date
    Apr 2013
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    Glockin, Pennsylvania
    (Montgomery County)
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    Default Red Dot Quick Tip I Never Knew About

    Flip up your rear small aperture sight and look through it at your dot for a smaller, crisper dot for precision shots. It's some sort of vision phenomenon and truly works. Try it!

  2. #2
    Join Date
    Apr 2008
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    New Oxford, Pennsylvania
    (Adams County)
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    Default Re: Red Dot Quick Tip I Never Knew About

    I don't understand the mechanism behind it, but it's equivalent to squinting. It sharpens you vision

  3. #3
    Join Date
    Apr 2013
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    "The Country", Pennsylvania
    (Chester County)
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    Default Re: Red Dot Quick Tip I Never Knew About

    I have an astigmatism, so when I look at my red dot through my smaller aperture, it helps a lot.
    "The Constitution is the guide which I will not abandon.” - George Washington

  4. #4
    Join Date
    Jan 2013
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    West Chester, Pennsylvania
    (Chester County)
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    Default Re: Red Dot Quick Tip I Never Knew About

    At the eye doctor, had difficulty when they go smaller alph's. They gave me a fine mesh to look thru and the alpha's were clear. It blocks the glare.

  5. #5
    Join Date
    Nov 2011
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    Bucks County, Pennsylvania
    (Bucks County)
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    Default Re: Red Dot Quick Tip I Never Knew About

    Vision tip for when you forget your glasses: make a fist, make a tiny hole in it that you can see through, sort of like a telescope. You will be surprised how you can suddenly read fine print without glasses. Has something to do with limiting the amount of light that gets into your eye.

  6. #6
    Join Date
    Apr 2012
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    North Hills, Pennsylvania
    (Allegheny County)
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    Default Re: Red Dot Quick Tip I Never Knew About

    For those without a aperture sight on the firearm. http://bulletin.accurateshooter.com/...-aid-old-eyes/
    Let me help you out. Which way did you come in?

  7. #7
    Join Date
    Jun 2010
    Location
    In the can, Pennsylvania
    (Montgomery County)
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    Default Re: Red Dot Quick Tip I Never Knew About

    As I understand it, the diopter helps you focus because it shortens your focal length and puts your focus point where it would be if your eye (still) worked perfectly.
    Bern-
    ---------------------

    https://focusers.com/pages/explanati...opter-strength

    Lens Focal Point.JPG

    Diopter Strength Explained

    Diopter strength refers to the optical power of a lens. Lenses with a focal length of 1 meter (about 39 inches) have a diopter strength of 1. Since diopter strength is based on the inverse ratio of the focal length, a 2 diopter lens is not 2 meters but 1/2 meter, a 3 diopter lens is 1/3 meter and so forth. This is important because magnification increases as the lens focal length gets shorter, which is why a prescription for a higher diopter number means you need more magnification.

    The optical power of the human eye is about 40 diopters. The eye of a normal young person can adjust an additional 20 diopters. By age 25 this focus flexibility is usually reduced to about 10 diopters. Due to natural weakening of eye muscles that focus your vision and hardening of the eye lens, by age 45 the human eye is typically a mere 1 diopter. It's this diminishing capacity for the eye to properly focus its lens, called presbyopia, that results in blurred up-close vision and warrants corrective glasses.

    Reading glasses compensate for the loss of natural adjustment. Optical power is additive so the correction is straightforward. An optometrist may prescribe a lens that increases the magnifying power of the eye, usually in steps of a quarter-diopter over a range of 1 to 3 diopters. Generally, the eye care industry classifies reading glasses lenses in diopter strengths that increase by a factor of .25 (e.g., +.75; +1.00: +1.25; +1.50; +1.75; +2.00; +2.25; +2.50; +2.75; +3.00 etc.). A quarter-diopter is a large enough step that most people can self-prescribe their own reading glasses by simply trying on different diopter strength lenses and reading the example text, as typically found in a drug or grocery store.

    Presbyopia sometimes affects your left eye and your right eye differently. Therefore, you may need, for example, a +1.50 in your right eye and a +1.75 in your left eye. This is normal, although many people can overcome their Presbyopia perfectly by using glasses that have the same diopter strength in each eye. Nevertheless, if you fall in the category of people who need differing lens strengths for each eye, you could be doing yourself a disservice if you bought a cheap pair of one-size-fits-all glasses that had the same diopter strength in both lenses sold in drugstores or on many Internet sites.

    Presbyopia is progressive, and therefore, the strength of magnification in your reading glasses will probably have to be increased every year or two. Moreover, you may find that your need for stronger and weaker lens strengths can fluctuate slightly during any given period. In fact, you may need a stronger lens strength to eliminate the blur when you read your newspaper in the morning than what you would need to read the same newspaper in mid-day. Or, you might require a stronger diopter strength for detailed, up close work as opposed to general leisure or office reading. That is why some experienced users of reading glasses have more than one pair, each with different diopter strengths. Click here for more information about presbyopia.

    The easiest way to find out the diopter strength you need is to visit a drug store, department store or other retail outlet that sells cheap reading glasses, and try on a few different strengths. If you have no idea where to start, consider using this average age formula: If you are under 40 years old, you probably should start with a +1.25 strength. Between ages 40 and 45, you probably need +1.75. At ages 45 to 50, you probably need +2.00. After age 50, you probably need +2.25.
    How can you have any cookies if you don't drink your milk?

  8. #8
    Join Date
    Nov 2018
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    Marple Newtown Square, Pennsylvania
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    Default Re: Red Dot Quick Tip I Never Knew About

    Quote Originally Posted by jthrelf View Post
    Flip up your rear small aperture sight and look through it at your dot for a smaller, crisper dot for precision shots. It's some sort of vision phenomenon and truly works. Try it!
    I'll test this out on my AR today.

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