TargetTalk

TomF wrote:I am getting older and my the lens that I have are not strong enough.

I have a pair of Varga 2000 and one lens has two dots and the other has three dots. I cant remember what those magnifications are, .25 and .50 or .50 and .75?

Whatever they are I need a stronger lens.

Anyone know what the dots represent on the lens?

Thanks!

RobStubbs wrote:

TomF wrote:I am getting older and my the lens that I have are not strong enough.

I have a pair of Varga 2000 and one lens has two dots and the other has three dots. I cant remember what those magnifications are, .25 and .50 or .50 and .75?

Whatever they are I need a stronger lens.

Anyone know what the dots represent on the lens?

Thanks!

Surely it doesn't matter what they are if none of them are right for you ??

Get yourself to an optician/optometrist and get the correct ones made up, and ask for a copy of the prescription.

Rob.

Rover wrote:Big mistake! You will have a mess on your hands.

Get one lens with your scrip plus the correction to pull the focus of your eye to the front sight. I'm assuming you have shooting glasses such as Knobloch or Champion, since you have the single lenses.

Your optometrist will tell the power of the lenses you have (for free).

Rover wrote:If you know the answer, why ask the question?

Rover wrote: Your optometrist will tell the power of the lenses you have (for free).

ShootingSight wrote:I recommend you don't mess with inverted bifocals to try and sight through.

THe correct answer is that if you do not want a bifocal to focus on the front sight, as such a close focus will excessively blur the target. If you go through the photographic math to calculate hyperfocal distances, and do the accompanying math to calculate lens strength (which is what I did), or if you dig through this forum to find threads from people who have determined what power worked for them, you will see that the correct answer is that you need to take your distance prescription, and add either +0.5 diopters if you are shooting a rifle, or add +0.75 diopters if you are shooting a carbine/AR or pistol.

Those two powers will locate your focal point so your eye's depth of field is centered between the target and the front sight, with the front sight being as close to the near edge of your depth of field as your target is to the far edge of your depth of field. In this condition, the total blur that your eye sees on either the front sight or the target is at a minimum. If you go up or down in power, you will gain on one or the other focus, but give up more on one than you gain on the other.

That is the lens you want to look through to shoot, and the distance you are focusing at is called the hyperfocal distance. You can google that term, and find lots of photography sights that explain it in more detail, but basically, if I want to focus a camera so a near subject is in focus, and the background is in focus as well, the correct focal point is the hyperfocal distance.

In addition, I agree with your notion of getting an ADD of about +2.00 diopters so you can see up close to adjust the sights. Note that an ADD of +2.00 will be very strong (focus at about 16"), because 'ADD' for bifocals is a delta value relative to the distance power, and since you already augmented the distance power slightly to get the the hyperfocal distance, a +2.00ADD is strong. However, for rifle, I like this, because if shooting prone, and you are slung in, the sights are closer than reading distance.

As to seeing downrange, the top of your left lens should be good for that.

BTW, this will be strange to the eye doc, but if you augment the right lens for shooting by eg +0.50, and have an ADD bifocal of +2.00 (ie 2.5 total power in the right bifocal), you will want to have an ADD bifocal of +2.50 in the left eye, so both eyes are seeing the same power when you look through the bifocals. Normally, ADD is the same for both eyes, so you'll need to explain to your eye doc that the right eye already has an add built in to the distance lens.