What's the purpose of the lens in shooting frames?

[Inspector 71]

Sounds like a silly question I know but what kind of lens is used? Is it the same prescription as you would have in say, your distance glasses?

Ta.

[Turnup]

No, the lens is to bring the foresight into sharp focus, so it focusses quite a bit short of distance vision. The selection of the correct lens is somewhat of a specialist area (there are specialist optometrists). For most people it is possible to get an appropriate lens by trial and error, but this will not work for all visions defects, such as astigmatism.

[Modski66]

Funnily enough, this morning, I have just ordered a lens for my frames. I have astigmatism and presbyopia, and up to now I have been using a pinhole to get something that resembles a sight picture.
I am hoping the prescription on order will sort things out ready for Tokyo...

I was torn between the focus being set on the front sight blade, or just a standard distance, I went for the standard prescription in the end, as I want to keep on using a pinhole. (Gasps of horror from the purists).

No doubt you will be given a selection of conflicting advice, but I feel as though it really comes down to what works for you.

Cheers,

Mark.

[tim s]

Yes the lens is there to focus the eye at the right distance, and thereby reduce fatigue of the eye muscles. The prescription is usually slightly different than distance which is calculated for infinity, and should definitely include any cylindrical correction for astigmatism. Rifle shooters tend to favour a longer focal length than pistol shooters, because they want to see the target (even if they aren't concentrating on it) whereas pistol shooters seem to like a shorter focus and a fuzzier target.

For rifle, a focal length about double the sight radius is common, as this still gives a sharp foresight, but the target is less fuzzy. Typically this equates to distance prescription +0.5. I'm slightly long sighted and wear glases with a + 1.0 lens, my shooting lens is +1.5. Without the lens I have to consciously focus on the foresight, which is tiring, and distracting.

[xbow]

I went to a specialist shooting optician at Bisley camp. It was a long time ago but I think I just gave him my normal prescription and he worked from that to make the lens. He may have given me a test as well but as I say it was many years ago.

[nickm marshall]

I have poor eyesight. I use both distance and reading glasses as I am over 60.

I use Champion Olympic shooting glasses fitted with a 42mm lens made to the same precription as my distance glasses.

I also use a diopter. With that fitted, i adjust the iris down until I have the front and back sight sharp, as well as the black circle of the target. Also closing my other eye.

I recently tried another lens, that had .50 added to my distance precription. However, that makes the target a bit blurred. So I had no confidence pulling the trigger.

I am fully aware that I should be area aiming and that the back sight and target should be slightly out of focus. With the front sight sharp.

However, think i am going to stick with what i think feels and works best for me.

[BigEars]

I took my Lp10 into Specsavers. They were fine about it.