Scope focus / parallax- eyeball it or by the numbers?

G

GJgo

Guest
I've got a question for you guys. I've noticed that when turning the parallax / focus knob on my scopes, they are not in their sharpest focus when the printed number on the tube matches up to the actual distance. So, the question is, for proper parallax adjustment should I be paying attention to the number on the adjustment ring or should I set it to where it is visually the sharpest?

Are all scopes in meters while I'm shooting in yards? Is the focus / parallax ring only accurate at one power?

I shoot at 2 ranges, both of which I've lasered to confirm distance. I've also shot at a registered benchrest range. I've seen the same thing with a Burris Fulfield, a Burris Black Diamond, and a Nightforce Benchrest scope.

At 100 yds actual, sharpest focus is at 75 on the dial. At 200 yds actual, sharpest focus is at 150 on the dial. Etc..

What gives? I'm just not sure if focus or parallax as printed is more important. Thanks!
 
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Disregard the numbers

Every scope is different, but I find the numbers on the scope bell or Parellex Knob, don't always get you in focus and Parellax free. It's a trial and error procedure. Adjust the Parallax knob until the target is in shape focus, and the move your head side to side and up and down the see if the CH stay on the same plane as the target. You may have to adjust a bit back and forth until you get the CH and Target Parallax free. You might want to put some type of mark at the correct spot if you shoot at different distances and have to re-adjust each time.
 
Bear in mind that if the manufacture has set his scale for any condition, it's likely to be with the eyepiece focus at zero dioptres. As most of us don't have perfect vision & need to adjust the eyepiece to get the crosshairs in acceptable focus, then it stands to reason that the parllax scale could be taken out of whack.

Of course, so I've heard (& confirmed in the case of a couple of VXIII scopes I own, Leupold has more difficulty than some achieving simultaneous parallax adjustment & sharp image focus with their side afjustment range. My little old 24x BR does both easily & consistently.
 
Install a clear cover "lense" on the occular end of the scope - draw a small circle in the center of this "cover lense" and keep this visually centered around the crosshairs and target and don't even worry about parallax anymore. This simply gives you some visual feedback that your eye is in the same place each time and takes parallax error out of the equation. It's simple, but it works...on ALL scopes. The size of the circle is up to you, smaller is usually better for me. I go with between 1/8" and 1/16" ID with a thick enough line so that - though out of focus to my eye - I can still descern it's position.
 
Vibe,

That's the case & exactly how I shot benchrest as a kid with an old gold ring Leupold 3-9 & a Sako L461 heavy barrel, but if you were to need to adjust focus for the full gamut of F class distances for example (300-1000 yards), then the target could tend to get a tad out of focus & hard to acquire some of the time. I guess that's why we sometimes see the function less exactly described as focussing the target.

John
 
John Kielly said:
Vibe,

That's the case & exactly how I shot benchrest as a kid with an old gold ring Leupold 3-9 & a Sako L461 heavy barrel, but if you were to need to adjust focus for the full gamut of F class distances for example (300-1000 yards), then the target could tend to get a tad out of focus & hard to acquire some of the time. I guess that's why we sometimes see the function less exactly described as focussing the target.

John
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Yep. Sometimes the "old" simple methods still help. And you are right - keeping the target in sharp focus is what helps me as well. Worrying about other factors is a distraction, so I try and keep those to a minimum.
 
Just curious:

I have always been told and have read in various places that sharp focus was less important than adjusting the scope so that the reticule does not move when slightly moving one's eye side to side whilst looking through the scope. I rarely find a scope on which the distance numbers correspond with the actual paralax removal process. I wonder if these scopes may need further adjustm by their makers? Considering what we pay for these things, they should work correctly, shouldn't they?

Contrary to what I have read, I adjust the objective until the reticle doesn't move then clear the focus up as best I can with the objective bell. That becomes somewhat of a balancing act.
 
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Bogus? I don't think I would go that far. If you don't have any other method of eliminating the effects of paralax then having that adjusted out is critical. Even if you can see it clearly - if you're not really pointed at it, you won't hit it.

But on the other hand, working on the principle of "You can't hit what you can't see" - the sharper the focus the better.

It's best to have both.
 
Thanks for the responses- that gives me something to work with.

On my Nightforce, I do notice that the parallax seems to be the best when it's set to the numbers and not to sharpest focus. However, when I'm looking at a BR target like this it's just a little straining to the eye because my eye's focus will float between the crosshairs and the target. The target will "float" into focus if I strain. Of course, this is also at 32x.. In this case adjusting the diopter only makes the CH fuzzier.

I've got a Super Sniper 16x on the way for a new 308 project, so 'll see how that one does in this regard as well.
 
Vibe,

How do you draw a circle with a 1/16 or 1/8 ID on a glass lense and then mount it center on the reticle? What do you use to actually make the line.? I have a scope that is marked 50 yards as minimum focus distance and it only goes to 67. Kinda hard to shoot 50 yard benchrest with the amount of parrallax it still has. Are you able to screw the new lens to the scope? Can I ship my scope to you for this service? Email me the particulars if you can do this. Max prairiedog_740@hotmail.com
 
Max Shaffer said:
How do you draw a circle with a 1/16 or 1/8 ID on a glass lense and then mount it center on the reticle? What do you use to actually make the line.? I have a scope that is marked 50 yards as minimum focus distance and it only goes to 67. Kinda hard to shoot 50 yard benchrest with the amount of parrallax it still has. Are you able to screw the new lens to the scope? Can I ship my scope to you for this service? Email me the particulars if you can do this. Max prairiedog_740@hotmail.com
Click to expand...

It may sound cheesy, but I use a Blizzard scope lense cover with a tight fitting cap. I locate the "center" of the cover by finding the exit pupil - With the scope zeroed to the rifle, place a piece of tissue inside the lense cover and aim at a good light source. When I first did this I did it with plastic lense covers and simply drilled a hole, but glass is clearer so I went to drawing the circle with a fine point sharpie as close to the center of the exit pupil as I could get with a drafting circle template. I've thought about using a stick on circle like the ones I used to use laying out circuit board masks but just never got around to it. But I'm sure those are still available at drafting supply centers. I'd stick that on the inside of the lense cover. What you use is not all that important, as it's just a reference to let you know where your eye is. The paralax resulting from the external mark is so great that it allows you to correct it by repositioning your eye - unlike the internal paralax.
Hope that helps.
 
Pete Wass said:
Contrary to what I have read, I adjust the objective until the reticle doesn't move then clear the focus up as best I can with the objective bell. That becomes somewhat of a balancing act.
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Pete,
Did you mean to say that you "....then clear the focus up as best I can with the OCULAR bell."? You clear up the focus with the eyepiece ?

That's the way I do it. Get the parallax totally out and then if the image is not sharp it's because the eyepiece isn't adjusted correctly to my vision.
 
Because the eyepiece setting is not as sharply defined, it is possible to have it set so that when the parallax is eliminated, by front or side adjustment, that the target is not as sharp as it is at a setting that produces some parallax. In some, but not all, of those cases, I have been able to work back and forth between parallax and eyepiece adjustments to produce settings that give peak target sharpness, zero parallax, and a sharp reticle. In those cases where this was not possible, scopes were returned to their manufacturers and came back able to be properly adjusted. In writing this on a public forum, I am well aware that some expert will may come to this thread and explain what an expert he is, an what an idiot I am for saying such a thing, that it is impossible, or that someone that they spoke with told them it could not be. This does not concern me. I have vision that corrects to 20/15 ( on a good day) and I am quite sure that I have done what I have described.
 
Whatever anyone else might say Boyd. That makes perfect sense, as those "special" cases would indicate that the objective lense was out of position relitive to the paralax adjustment position setting. Some people have made those corrections themselves but there is a very real risk of losing the integrity of the internal seals and or gas mix - the manufacturer is better equipped to perform that correction.
 
Another way.

There is another way to have sharp focus and minimize the remaining parallax. If you move your head back from the scope the field of view decreases to a small circle. It is easy to center the cross hairs in this smaller circle. This puts your eye in the same position each time thus minimizing the remaining parallax.

Good Hunting... from Varmint Al
coyotel.gif
 
For any kind of shooting I adjust the eyepiece so that the reticle is comfortably in focus and sharp. I then set the objective so there is no parallax movement of the target relative to the reticle when I move my eye laterally. I then quit screwing with it and shoot. I never try to chase the focus of the target for better quality image.

The target never will look as sharp as the reticle because it's image is affected by 100 or more yards of sun warmed air while the reticle image is not. The target image resolution can change rapidly with time from "mirage". Changing objective or eyepiece focus can only hurt the parallax or reticle focus. Aiming at the centroid of a fuzzy image is as good as can be done. Waiting for the image to improve can certainly help but that may or may not happen. I don't change any adjustments if I choose to wait for the air to improve. The silhouette target in this photo is fuzzy but it's not out of focus. It's just the result of random atmospheric refraction. There is no scope adjustment which can correct it, and no brand, size or magnification of riflescope which could do significantly better.
http://i140.photobucket.com/albums/r37/MGD45/700 yard day/700ydreticle.jpg

Objective focus can change a little if the scope changes temperature so I check the parallax occasionally but never try to change it unless I see parallax movement. I will adjust the eyepiece if my eye feels strained or the reticle doesn't appear sharp. An eye can change some with time from fatigue or light level. Most commonly I'll set the adjustments once and not change them for a day's shooting unless the target distance changes.

It is tempting to try to obtain sharper target images but I've never found that doing so improves accuracy. I know of no logical reason why it should either. Just my experience and opinions.
 
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Are you aware

Vibe said:
Whatever anyone else might say Boyd. That makes perfect sense, as those "special" cases would indicate that the objective lense was out of position relitive to the paralax adjustment position setting. Some people have made those corrections themselves but there is a very real risk of losing the integrity of the internal seals and or gas mix - the manufacturer is better equipped to perform that correction.
Click to expand...


that most of the scopes we use are not filled with anything but ambient air? Most of mine and I think all my competition scopes are not pressureized. They are washed with Nitrogen when assembled but that's it.

Beyond that, some of the Competition scopes have the optional adjustable occular feature. This certainly is not affecting any internal gas situation in the scope (s).
 
Yes

crb said:
Pete,
Did you mean to say that you "....then clear the focus up as best I can with the OCULAR bell."? You clear up the focus with the eyepiece ?

That's the way I do it. Get the parallax totally out and then if the image is not sharp it's because the eyepiece isn't adjusted correctly to my vision.
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This is what I am saying. I find that with my 6 X scopes particularly, I have to re-focus the bell to sharpen up the reticle immage often each day I use them. and in doing so the total focus will be aided; almost always.

I have yet to need to move the bell on my Leup. Competition scope or scopes that I have had once they are/were focused. They do have that nice feature to move them back and fourth easily as do the Burris HBR II's.
 
Pete Wass said:
that most of the scopes we use are not filled with anything but ambient air? Most of mine and I think all my competition scopes are not pressureized. They are washed with Nitrogen when assembled but that's it.

Beyond that, some of the Competition scopes have the optional adjustable occular feature. This certainly is not affecting any internal gas situation in the scope (s).
Click to expand...
If you don't mind water vapor condensing on the inside of your lenses during a cold match, feel free to take apart and readjust anything you wish, many do. My point was that, though I never implied any sort of pressurization, the gas content inside the scope was fairly tightly controlled to exclude water vapor (in particular). And that the manufacturer was equipped to handle that exclusion better than most individuals.
 
I have never

Vibe said:
If you don't mind water vapor condensing on the inside of your lenses during a cold match, feel free to take apart and readjust anything you wish, many do. My point was that, though I never implied any sort of pressurization, the gas content inside the scope was fairly tightly controlled to exclude water vapor (in particular). And that the manufacturer was equipped to handle that exclusion better than most individuals.
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experienced any moisture in any of my scopes over 15 years or so and I live in a very inhospitable place. Others may vary.

The important thing here is the Mother of Invention is always around and some of us choose to facilite her. Scopes are simply a tool as are barrels or actions or anything else. They can become a cost of doing business as those other things do. Some of us choose to do what makes life easier for us and are successful at it. Doesn't make it right or wrong but it says we are less anal than some may be. We walk on the "wild Side" if you will. If one wants to win, sometimes one must take a road less traveled.
 
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