Help with Parallax & Image Focus

[NealWright]

One of my goals this spring is to work out my parallax issues. First off I'm using a Savage F'Class & Sightron 36x. And, I also have horrible eye sight ... I think my last prescription was 6.5!

Regardless, every scope I have ever used has major parallax reticle movement at a setting that has the target image at it's clearest. Matter of fact, I can't think of a scope that wasn't set at "infinity" for focusing anything past 100yds.

So, what should be my goal?

Find an optimal parallax setting ... that has the whole image blurred so bad, I couldn't tell if I had parallax issues, or not? Or, focus the image, and fight to get a perfect cheek position each time?

Any offers of advise?
Thanks, Neal

 

[MrMajestic]

Neal, Let 'em get closer and use a Shotgun!
Sorry, I couldn't resist. I use target clarity to schedule my Optometrist appointments.
Hope somebody can help you.

 

[NealWright]

OK ... I understand everything in his article (couldn't recite it), but I still can find no reference to the images being out of focus when zero-parallax is set.

I know I can't be the only one with the this problem, as I regularly here the AO referred to as a focus ... and it does that quite well. But what are the options when zero-parallax setting is a blurry blob?

Thanks again, Neal

 

[NateHaler]

OK ... I understand everything in his article (couldn't recite it), but I still can find no reference to the images being out of focus when zero-parallax is set.

I know I can't be the only one with the this problem, as I regularly here the AO referred to as a focus ... and it does that quite well. But what are the options when zero-parallax setting is a blurry blob?

Thanks again, Neal

First, ensure that your focus is sharp, i.e. that the reticle is distinct the instant you peer through the scope. This is easily ascertained by looking at a daytime sky, rather than having other images besides the reticle in view. To make a focus change, it usually needs to be rather dramatic, i.e. several turns of the focus ring, before you'll notice much of a difference.

Parallax elimination is NOT the same as focus. You're fooling yourself, and detracting from your ability to shoot well at distance, if you're using parallax adjustment to focus the target into sharp relief. Parallax elimination means optically placing the reticle and the target on the same focal plane. Which means that as you might move your eye behind the scope, the reticle will not appear to move relative to the target.

Imagine being 100y away from a target, and having already placed a wooden stake directly in line with the target but at only 90y away. As long as you stay in that one spot, the stake and the target are aligned. But if you take a step or two to the side, you'll now see that the stake and the target are no longer aligned. However, if you placed the stake right in front of the target at 100y, meaning touching the target or nearly so, then it doesn't matter if you take a step or two or ten to the left or right. The stake and the target are on the same plane. That's what you're trying to achieve with parallax adjustment.

If your focus and parallax cannot be set to achieve your objective (no pun intended), then you should contact Sightron and arrange a repair or replacement.

 

[Fred Bohl]

Neal,

From your description of your problem (needing the AO set to infinity) and your "horrible eyesight" comment, I must conclude that the root cause is your eyesight but the functional problem is actually your corrective lens. I will also assume that you wear corrective glasses and further that your rifle and shooting position are reasonably normal.

The lens of your eyeglasses is ground to place the spot of proper correction directly in front of the relaxed eye gaze strait ahead with your head in an upright position. The stronger your prescription the smaller the spot of proper correction. Note that when in a conventional shooting position you are normally looking through a spot on the lens that is toward the top of the lens and near your nose (far away from the portion of the lens that has the optimal corrective shape). Also note that if you are using blended/multivision lenses the spot used for shooting is typically out of the portion that is ground with any part of your prescription.

The range of eyepiece focus is very limited (typical is -3 to +3 diopters) so if your prescription requires more correction, you cannot use the simple expedient of not wearing corrective glasses (only zero correction safety gasses) and using the adjustments on the scope. Alternatively you can have shooting glasses made to have your distance correction only and optimized for location at the aiming location. If you can wear contact lenses, you can have one made with your distant vision prescription only for your aiming eye and wear that with zero correction safety glasses.

Fred

 

[NealWright]

Well, I think that's trying to help ... but I'm really confused

Oh yeah, I definitely have corrective lenses ... I wear contacts, like I said in the 6.5 range. I mentioned my problem to the eye doctor last time, but he didn't seem to offer any help.

Maybe it wouldn't be bad to contact Sightron? They've been excellent so far! Just seems to be non-manufacturer related, since I have the same issue on all scopes I've used (even tonight).

FYI ... I just wanted to clarify too, I do understand the concept of parallax, and I do have have my reticle focused properly.

Thanks, Neal

 

[BoydAllen]

You need to get your eyepiece focused exactly at the plane of the reticle, when it is, peak target focus and zero parallax will occur at the same point of objective, or side focus adjustment. The problem is that the directions that have been furnished to you earlier in this thread is that the writer assumes that if you follow the given procedure that you will accomplish this. Many times this is not the case, and when it is not, you will have a problem, and not be able to have zero parallax and peak image sharpness at the same point of adjustment. Having no wish to provide entertainment with a protracted on line argument with anyone who prefers to believe someone else (their perfect right) I suggest that you PM me, and we can get together on this matter and solve your problem. It may be that the eyepiece lacks sufficient range of adjustment. This can be dealt with.
Boyd Allen

 

[dksac2]

It may help to have another shooter who knows what he is doing set up your scope, of course that is still not going to deal with the issue of the focus on the rear objective.

Sorry to hear of the bad eyesight, I kow mine is not what it used to be with handguns since I have had glasses.

I hope you get it figured out.

My Best, John

 

[Dennis Keefer]

Neal;

My 2 cents - PM Boyd.

I shoot Ground Hog matches in Pennsylvania at 200 / 300 / 500 yards. Due to my eye problems, I spent most of a summer getting my 36X target scope set -up.

Good Luck! Hang in with it, you might want to talk to another eye doctor about specially ground glasses, not plastic.

 

[Leaddog]

BoydAllen knows what he is talking about.

First off.... Make sure your eye glass prescription is up to date.

Adjust eyepiece focus. If your reticle and target relationship does not come together in sharp focus without movement, then your eyepiece is not adjusted properly. You can adjust the eyepiece focus by looking through your scope into a clear sky, or white wall.

To check parallax, remove your head from the stock and look through your scope moving your head up and down and sideways. If there is any movement in the reticle/ target relationship, the parallax is not properly adjusted. If you must adjust to a slightly out of focus image to steady the image, your eyepiece is not properly adjusted.

Remember, the side focus knob is a parallax adjustment. If your eyepiece is adjusted correctly, then you will achieve zero parallax at the point of sharpest focus resolution.

 

[BoydAllen]

To reiterate what I wrote earlier, if, after you have focused your eyepiece for reticle sharpness while pointed at open sky or a blank wall, your target is not fully sharp when you have zero parallax, you should make very small adjustments to your eyepiece, trying both directions from where you started, while at the bench, and looking at your target, refocusing for target sharpness after each eyepiece adjustment, and then checking for parallax. Do this until you have peak target sharpness, and absolutely no parallax at the same objective or or side focus adjustment.

 

[JRS]

One of my goals this spring is to work out my parallax issues. First off I'm using a Savage F'Class & Sightron 36x. And, I also have horrible eye sight ... I think my last prescription was 6.5!

Regardless, every scope I have ever used has major parallax reticle movement at a setting that has the target image at it's clearest. Matter of fact, I can't think of a scope that wasn't set at "infinity" for focusing anything past 100yds.

So, what should be my goal?

Find an optimal parallax setting ... that has the whole image blurred so bad, I couldn't tell if I had parallax issues, or not? Or, focus the image, and fight to get a perfect cheek position each time?

Any offers of advise?
Thanks, Neal

Listen to Fred Bohl

 

[timeout]

To reiterate what I wrote earlier, if, after you have focused your eyepiece for reticle sharpness while pointed at open sky or a blank wall, your target is not fully sharp when you have zero parallax, you should make very small adjustments to your eyepiece, trying both directions from where you started, while at the bench, and looking at your target, refocusing for target sharpness after each eyepiece adjustment, and then checking for parallax. Do this until you have peak target sharpness, and absolutely no parallax at the same objective or or side focus adjustment.

Thanks for writing this. As always, your knowledge and ability to articulate have shown through. My eyesight is pretty good for my age. Distance is great, for reading a 2.0 seems right. I do not wear any prescription eyewear when shooting. That being stated, I never have my sharpest image of the target when my parallax is correct. This is with several Nightforce NXS scopes. A friend of mine has the same issue. When I get some time and the weather is better, I shall work on correcting this using your advice. Thanks!

 

[BoydAllen]

Let me know how that works out for both of you. Good luck. You should be able to solve your problems. Just remember, for that final, at the bench fine adjustment, you WILL be looking at a target, and make very small moves on the eyepiece, especially if is the European, fast focus type. If going a little way in one direction, and then refocusing on the target for sharpness, makes the parallax worse, go back to where you started and try the other direction.

Once when I was at the range with a friend who had brought rifles with both the NSX and BR scopes, we both noticed that the side focus required a lot of fiddling with to keep in adjustment, like it was not holding precisely while shooting. The BR did not have that problem at all. If it had been my scope, I would have been on the phone with NF that day, about getting the problem resolved.

 

[normmatzen]

Boyd pretty much got it right on the button!

There is one more item no one has mentioned tho. Side focus scopes have a fairly complex linkage from knob to lens hangers. That is why the BR scopes are less finicky. Some side focus scopes require that every time you make an adjustment, you must approach the final adjustment from the same direction as the back lash in the scope is only correct from one direction, such as from infinity to final adjustment. Different brands may require adjusting from close toward infinity. My SIII Sightron isn't too picky but some scopes are. Of course, my N-F BR does not have that problem.

 

[M-61]

This is worth reading and gives some plain answers:

http://www.snipercountry.com/Articles/Parallax.asp

 

[AckleymanII]

One thing that I have found is that front focus scopes have a much wider range of "focus' vs side focus. Side focus is real touchy on a focus, and for that reason, I prefer the front focus scopes.

 

[Alexander-M]

I have had the same issue of not being able to get rid of horizontal parallax since I bought my first Nightforce NXS about three years ago, and it continued with the newer NF Competition. However, I have zero vertical parallax - I can move my head up and down and the crosshairs stay put on the target. But when I move my head sideways slightly, the crosshairs move from 1/2 to 1-MOA. I posted (here) this problem six months ago, and tried several of the suggested fixes, but I still have the problem, although I have to admit that it is somewhat less. I think adjusting the eyepiece did help, but I find that it is difficult to detect much sharpness variation when turning the eyepiece.

it normal for a scope to be parallax free in one axis (vertical) but exhibit parallax in the other axis (horizontal, in my case)?

Thanks!

Nando (Alex)

 

[BoydAllen]

The article has a lot of good information, and one glaring error. If you follow his instructions to the letter and have a little parallax when your objective or side focus is set for peak target sharpness, or you have a slightly out of focus target image when your objective or side focus setting gives you zero parallax, his instructions will have come to their limit. These situations can be very common, and he offers nothing in the way of advice as to how to fix them. I know how, and have done it many times, and so can you, but you will have to do something different than what he recommends.

 

[M-61]

The article has a lot of good information, and one glaring error. If you follow his instructions to the letter and have a little parallax when your objective or side focus is set for peak target sharpness, or you have a slightly out of focus target image when your objective or side focus setting gives you zero parallax, his instructions will have come to their limit. These situations can be very common, and he offers nothing in the way of advice as to how to fix them. I know how, and have done it many times, and so can you, but you will have to do something different than what he recommends.

I posted this not as the most comprehensive article ever written on the subject but rather a quick read into the world of parallax that gives an excellent overview with where to start and what it actually is. For someone who may be confused as to what parallax is (not helped with scope manufacturers putting yardage marks on it) I think it is worth reading. Not so much as an 'error' rather he stops short.