TargetTalk

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PostPosted: Tue Jan 09, 2018 1:31 pm 
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Joined: Mon Sep 05, 2011 10:35 pm
Posts: 20
Hello ,

I've been noticing lately that my front sight picture is MUCH clearer/sharper when I close my non-shooting eye. despite having a translucent blinder on my rear sight.
I cannot however, close my non-shooting eye for long periods of time.

Any suggestions as to how I can get that same sharp image without closing my non-shooting eye is appreciated.

Thanks


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PostPosted: Tue Jan 09, 2018 2:21 pm 
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Joined: Fri Aug 11, 2006 2:01 am
Posts: 116
Location: New Zealand
I have the same problem. As a solution I use a thin black strip as a blinder, approx 6mm wide for 50m shooting & 13mm wide for indoor shooting, in front of the non-aiming eye. The black improves the sight picture contrast markedly while the thin strip allows enough ambient light around the sides to keep the non-aiming eye's iris from opening up too much.
The initial problem is caused by slight dominance of the non-aiming eye, a problem that crept up on me over time. The lack of contrast is because the brain is using the non-aiming eye's picture of your white translucent blinder, not the aiming eye's view of the sight picture.
Cheers
Martin


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PostPosted: Tue Jan 09, 2018 4:41 pm 
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Joined: Sat Nov 15, 2008 4:20 pm
Posts: 5182
Location: Scottsdale AZ
It could be that you're squinting. Had your prescription checked lately?


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PostPosted: Wed Jan 10, 2018 4:46 am 
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Joined: Mon Jan 03, 2011 11:33 am
Posts: 1350
Location: Taunton, Somerset
Jenni,

A translucent blinder is normally recommended to avoid straining your eye muscles. The idea is that the iris of the non-aiming eye can open in tandem with the aiming eye. As Martin notes a translucent blinder doesn't seem to work if you are cross-dominant. There have been several threads on this forum about cross-dominant vision, and a dark blinder seems to work better. Have you ever checked which us your dominant eye?

Rover's suggestion of going to a good optician, preferably one who understands rifle shooting, is sensible. Not all opticians get what we need and assume that OK distance vision is enough. A lens prescribed specifically for shooting will give a good sight picture without tiring your eyes.


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PostPosted: Wed Jan 10, 2018 4:52 am 
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Joined: Sun Sep 04, 2016 10:59 am
Posts: 550
Location: A new global Great Britain
I find any light in the other eye very distracting and always use a black blinder.
I have shot with right eye and lately with left eye on Mec Swap and need blackout on non aiming eye in both cases. Personal choice . Try it with full 30mm black tape.


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PostPosted: Wed Jan 10, 2018 12:41 pm 
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Joined: Mon Sep 05, 2011 10:35 pm
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Martin H
Rover
Tim S
TenMetrePeter

Thanks a lot for all the suggestions .

Is there something specific I need to point out to my optician to make him understand the difference between regular lenses and shooting lenses?


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PostPosted: Wed Jan 10, 2018 1:57 pm 
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Joined: Sun Sep 04, 2016 10:59 am
Posts: 550
Location: A new global Great Britain
Shooting prescription is your normal distance prescription with added magnification to focus at (I think) 2 metres from the shooter i.e. Distance prescription +0.5 dioptres spherical. You choose whether to have the prescription as shooting spectacles worn on the head or all in a single lens mounted on the rear sight or your normal specs with added +0.5 lens on rearsight. The iris rear sight gives a depth of field anyway so try the smallest possible like 1 mm aperture if adjustable.
I just use my distance prescription only with 1.2mm iris.

However general eye health and ageing also needs looking at.


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PostPosted: Wed Jan 10, 2018 2:06 pm 
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Joined: Mon Jan 03, 2011 11:33 am
Posts: 1350
Location: Taunton, Somerset
Jenni wrote:
Is there something specific I need to point out to my optician to make him understand the difference between regular lenses and shooting lenses?


Focal length: you want a shooting lens to focus your eye at a specific point rather than infinity. Most folks find a focal distance of 2x the sight radius works best, as the target is a little clearer than focusing dead on the foresight. In technical terms you want the hyper focal distance. For a typical air or Smallbore (no long extension tubes) you need a +.0.5 lens:if you already need a correction for distance add the +0.5 on top. For example, I'm slightly long-sighted and have a +1.0 prescription for everyday use. My shooting lens is+1.5 (1 + 0.5). My first lens in my 20s was just +0.5 as I didn't need any other correction.


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PostPosted: Thu Jan 11, 2018 9:24 am 
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Joined: Fri May 18, 2012 9:37 pm
Posts: 263
Location: Cincinnati, OH
It has been said, but I'll repeat. You want your eye's relaxed focus to fall at the hyperfocal distance of the front sight. Hyperfocal reflects the optical average between focusing perfectly on the sight and focusing perfectly on the target. If you were to focus perfectly on the sight, your target would be too blurry, and if you fous on the target, your sight is too blurry, so the best sight picture is formed by focusing between the two, which will center your eye's depth of field between the two, so both are almost in focus at the same time.

As the target is at optical infinity, the math for this is driven by the distance to the front sight. For most match rifles, this works out to needing +0.50 diopters added to any distance vision prescription you have.

If you need help getting a lens made, get in touch with me at ShootingSight.com, and I can make it for you.

Art

_________________
Art Neergaard
ShootingSight LLC
www.shootingsight.com
shootingsight@fioptics.com
513-702-4879


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PostPosted: Fri Jan 12, 2018 9:31 am 
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Joined: Tue Sep 11, 2007 6:18 pm
Posts: 21
Art,

I wear a -6.50 contact lens for shooting, and have for many years. I have a slight difficulty getting a good focus on the front sight. Because my correction is at the -6.50 level, the next available contact lens power is -6.00. I am thinking of trying the lens holder that connects to the rear aperture as it appears as though that may be the best and easiest way to keep the lens square to the sighting plane. I am thinking a +.25 may be perfect. I do need reading glasses in low light and my sight radius is close to 38 inches.

Any guidance is appreciated.

Best, Mark DelCotto


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