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Eagle Eye Question

Posted: Sun Aug 21, 2016 12:29 pm
by Paul
When using an Eagle Eye in the foresight, do you still have to wear your shooting glasses or they become useless ?

Thanks !

Re: Eagle Eye Question

Posted: Sun Aug 21, 2016 12:38 pm
by Tim S
Paul wrote:When using an Eagle Eye in the foresight, do you still have to wear your shooting glasses or they become useless ?

Thanks !
I'd say yes. An eagle eye is a +0.3 or +0.5 dioptre lens, that at foresight distance magnifies the target. It does't do much for the focus on the foresight, and does diddly squat for astigmatism. So, if you wear glasses to avhieve a good focus on the foresight, and/or have astigmatism, you'll need to keep wearing these.

Re: Eagle Eye Question

Posted: Sun Aug 21, 2016 12:48 pm
by Paul
I'd say yes. An eagle eye is a +0.3 or +0.5 dioptre lens, that at foresight distance magnifies the target. It does't do much for the focus on the foresight, and does diddly squat for astigmatism.
Thanks for your reply Tim !

Would it be the same with the diopter in the rear iris ?

Re: Eagle Eye Question

Posted: Sun Aug 21, 2016 1:49 pm
by Tim S
If you mean pairing a rear diopter and eagle eye, yes, although as the rear diopter also magnifies the whole sight picture you'll need to check in the relevant rulebook whether a diotpter +eagle eye is legal. This combination is not permitted under British NSRA rules.

If you mean using a rear diopter with glasses, I'd think why? The dioptre adjusts for focal length, which is what a correctly prescribed lens should do anyway. If you need to use both, the prescription in the glasses isn't right.

Re: Eagle Eye Question

Posted: Sun Aug 21, 2016 4:42 pm
by ShootingSight
Get rid of your shooting glasses if you have +0.50 in front, get lower power shooting glasses if you have the +0.3.

In order to see the target, your eye theoretically needs no extra strength, ie zero diopters.

When you add the +0.3 (truly +0.25, but they round off), or the +0.50, it will actually fuzz the target. However because the distance from your eye to the lens is so great, there is also a magnification. Shooters find the magnification more useful than the negative of the slight fuzz.

Your shooting glasses are also a positive diopter, usually about +0.50.

Lenses add, so if you have +0.50 in your shooting glasses, and then add another +0.50 in the front sight, you end up with a power that is much too strong to see the target. Here, your best bet for a compromise between seeing the sight and seeing the target is no power in the shooting glasses.

With a +0.25 in the front sight, the lens math suggests that a +0.25 in your shooting glasses will give you the best balance.

Re: Eagle Eye Question

Posted: Sun Aug 21, 2016 4:50 pm
by Rover
You don't have to fart around with all that. Buy a pair of glasses with astigmatism corrected and about +0.50 over your distance correction built in. One lens, no problems.

Re: Eagle Eye Question

Posted: Sun Aug 21, 2016 7:46 pm
by Anschutz
Rover wrote:You don't have to fart around with all that. Buy a pair of glasses with astigmatism corrected and about +0.50 over your distance correction built in. One lens, no problems.
Let me see . . . Art advised me several years ago, so I "farted" around with his advice on vision correction, "farted" around and earned Master with irons. Shot several more years, eyes changed, ordered Art's lens test kit, "farted" around with it, got a new lens and back on irons shooting Master scores again after having to use the scope. Someone once told me many years ago while I was trying to counsel a Sergeant, "Captain, you cannot reason with ignorance." F-a-r-t.