Eyepiece focus….How to get it perfect?

[nksmfamjp]

I have a new benchrest scope. I think the crosshair is 0.01 thick and dot is 0.1 thick. It is the Sightron S3 45x. How can I get the eyepiece focus perfect? I have a hard time seeing the whole reticle perfectly for some reason.

Basically, my standard method has been to crank the side focus to infinity and focus looking at blue sky. Then adjust until it looks clear. This works great on hunting/tactical scopes, but this thin crosshair makes it much harder to judge.

I have also set a scope on a 100yd target set to zero parallax and then adjusted the eyepiece until all was in focus…..is this a legit method? I’m not really sure.

 

[JohnKielly]

Crosshair focus should be independent of parallax adjustment, though not always so. However, always focus crosshairs first. They should then stray focused irrespective of how much you change the parallax adjustment for the distance.

I've found that I can best adjust my crosshair focus by looking at our white refrigerator from about 4-5 feet and cranking until I got the best image. However, on my older Leupold 8-25 the adjustment was so slow that I would wind one way until it was definitely unfocussed, then back the other way until it lost focus, then halved the adjustment.

 

[jpx2rk]

I have a SIII 45x on my RFBR rifle, and used the 50y target stands with a white target up on the backer to set it for my eyes. I just flipped a match target to show the plain backside of it and then flipped it back over to show the bulls once I had it set to check it before I started the zeroing process.

 

[243winxb]

Set parallax adjustment on the scopes yardage mark for 100 yards, while aiming at white paper @ 100 yards.

Adjust eye piece.

Fine tune parallax adjustment for each yardage change. Not all yardage markings on the scope are correct.

Corrective lenses should be 20/20 for distance vision.

 

[coldboreshot]

I have a new benchrest scope. I think the crosshair is 0.01 thick and dot is 0.1 thick. It is the Sightron S3 45x. How can I get the eyepiece focus perfect? I have a hard time seeing the whole reticle perfectly for some reason.

Basically, my standard method has been to crank the side focus to infinity and focus looking at blue sky. Then adjust until it looks clear. This works great on hunting/tactical scopes, but this thin crosshair makes it much harder to judge.

I have also set a scope on a 100yd target set to zero parallax and then adjusted the eyepiece until all was in focus…..is this a legit method? I’m not really sure.

When you say your not seeing the whole reticle perfectly, are you referring to the entire sight picture through the scope or the reticle is just not crisp and defined. If its the whole sight picture, your eye-relief distance is not correct which in turn complicates adjusting the eyepiece for a crisp reticle. If its just a muddy reticle, you just need to adjust the eyepiece for proper focus.

 

[nksmfamjp]

the reticle is just not crisp and defined

This seems to be my issue. There are some good ideas in here to try.

 

[243Lapua]

Do you use eyeglasses. Are you near or far sighted.

I am near sighted and I usually have to screwout the eye piece until I get a crisp image, than I play with the paralax to adjust for distance.

 

[KY_Windage]

On a sunny day I might get an entire reticle in pretty sharp focus, but most of the time I have to be satisfied with merely getting the center portion in sharp focus. I have always assumed it is because the reticle is on a flat plane, meaning that the middle portion is closer to your eye than the extremes are. The difference in distance means the diopter is not going to be exactly right for some part(s) of the reticle.

If you look at any particular part of the reticle your eye will usually correct for the error, especially if you have youthful eyes with those very flexible internal lenses. To a kid, every reticle they look at is in focus, where us old guys have to carefully focus every reticle. Because of this I often notice that while the center portion of the reticle is well-focused on the target, the rest of it is slightly out of focus.

 

[rckendall]

Remember to look away from the scope after a couple seconds (?) and let the eye readjust. Then look again through the scope. The eye will try to correct an out of focus image, so the quick first look is what you must try to get correct.

 

[Gil P.]

I've used the blue sky method with limited success. I

Try this:

You must do this at night, say around 8pm, indoors with no harsh lighting. I spoke with an optical engineer who said when your pupils are dilated, the accommodation range of your eye decreases and becomes more sensitive as to what's actually in focus.

Set parallax to infinity
Set magnification wherever your reticle just starts to become useable (if it's a ffp). For me this was about 8x-10x.

Set diopter until the reticle is completely out of focus.

Do the same process you would when looking at a clear blue sky, then through the scope. This time you'll be looking at the wall, try not to focus your eyes on anything before looking through the scope. Adjust diopter until it is in focus.

You won't be able to focus the entire reticle on all scopes, especially at a lower mag range. Make sure the center of the reticle is focused.

I can focus the entire reticle on my 5x scope, and can't in my 7x scope. I understand it's normal for scopes with a higher mag ratio to not have the entire reticle in focus at low magnification on ffp scopes.

 

[CJ6]

Get your eyes checked...This is the problem I was having and found out I had cataracs in the right eye.