# Parallax Explained



## glenway (Mar 27, 2011)

I've encountered parallax over the years and some people just don't realize it's there, when in fact, it is. Others think all they have to do is set their parallax adjustment according to the range listed on the scope and that's all there is to it. But, when you mess with the diopter setting (at the ocular lens - the one near your eye) - you can forget about those settings.

I put together a short piece on the issue here: http://www.ammoland.com/2015/08/rifle-scope-parallax-adjustment-video/#axzz3hsQ9br00


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## youngdon (Mar 10, 2010)

A great easy to follow guide on proper adjustment. Thanks Glen !


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## glenway (Mar 27, 2011)

Thanks, YD. Some guys just don't realize what's going on.

My eyes are bad and always have been, but I can still see as well as the next guy by tweaking some glass. Obviously, there's a bit more to the art of shooting, but it only makes sense to consider/eliminate things we can control that would otherwise hinder performance.

I always want to know if it was my ability rather than getting into some tail-chasing gremlin search.

Been there, too.


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## youngdon (Mar 10, 2010)

Many people I've encountered through the years had no idea that the ocular lens adjustment could make a whole lot of difference in their scopes clarity, but that falls in line with the number of people who never read the instructions that come with a product because they assume they know how to use it.


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## 220swift (Mar 2, 2011)

Good stuff Glen, This is one area I spend a lot of time practicing with the Swift and the 8X32X50 scope before calling season starts. The more I work with the parallax, the tighter my groups get and the tighter the groups get the more confident I get for the season.


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## 220swift (Mar 2, 2011)

Short, I thought you worked for a firearms, sporting goods dealer/store?


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## glenway (Mar 27, 2011)

OK, Short.

When I set the parallax adjustment to 100 yards at a 100-yard target on my (Leupold Mark AR 6x18x40) without first setting the ocular lens the reticle is so blurry, I'd never be able to define a basketball at that range. But, when I first set the ocular lens according to instructions and make the reticle clear, that 100 yard setting is so blurry on a target and so affected by parallax, I'm totally out of business. But with a clear reticle, adjusted per directions, the only way I can make out a target at 100 yards is to set the parallax at a whopping 400 yards and presto - no parallax.

Please explain. And, don't tell me the scope is junk, either.

And, by the way, when I discussed this with Dave Domin at Leupold, he said my experience was normal, because moving the diopter from zero will always cause this to happen.

The link you provided does not refute what I've stated, either.


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## glenway (Mar 27, 2011)

Thanks, Short.

After reading your post, I went to the safe and took out another firearm with a Leupold Vari XIII 6.5x20 AO scope and I couldn't get the thing to show any parallax at 100 yards with the AO dial set at 100 - no matter what I did with the ocular lens.

Here's how I appear to have to gotten mislead. Leupold sent me the scope for the .17 WSM project and when the ammo was found to be defective, I needed more than the agreed-upon 60 days, so I called Dave Domin of Leupold to get an extension. While on the phone, I asked him about the parallax issues I was having and he told me that adjusting the ocular setting would cause the parallax issue I was experiencing. I bought it. Dang.

Now, I must have another chat with Mr. Domin and am not sure if this scope will do the job. I don't trust it now.

And, wouldn't you know it, Winchester just sent me the tracking number for my replacement ammo, which is set for delivery today.


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## Antlerz22 (Apr 18, 2011)

Ran into parallax with an old Redfield wide-view 3X-9X. Took it (lived in Denver then) to Redfield and was told by one of the factory repair techs. mine was unfixable. He then told me how to "spot" parallax and what to try to do to "dial" it out. As in everything there is a default/starting point. Set your scope objective to 100 yds, minimum power, and target exactly 100yds. THEN set your rear (ocular lens) for YOUR eye. Once all is clear (TARGET AND CROSSHAIRS), then all issues on being on, have been done--FOR 100 yds. For further ranges and power settings-- to identify parallax if you have it-- set what power you want to use (variable scope) then aim/look through while moving your head in small circles till you find "center", also simultaneously move head slightly forward/backward from the scope, till the "black-edges" disappears. When crosshairs are centered and view is "full" (no black edges-and edge to edge full view/bright) your eye position is correct. Then simply see if the target is razor sharp, ALSO the CROSSHAIRS have to be razor sharp. If one or the other is slightly/majorly blurry you have parallax. To reduce/cancel it out you turn the ocular till both target and crosshairs are sharp, if still one or the other blurry--then adjust the objective (if yours adjusts). If not and one or the other still blurry, and after proper head and eye placement in relation to scope; then your scope is not going to group good period. It at that point is operating beyond the quality of the scopes lenses, and adjustment parameters. Time for a hammer and a new scope. I've learned to almost instinctively, get on the comb of any scoped rifle-- mine or not; and quickly acquire eye center as I'm targeting. It presents no problem at stationary targets nor moving ones. And almost all brands have some parallax to some degree, and todays scopes can all about eliminate it with proper identification and adjustments. Its spotting it when it appears (some scopes only do it at higher power) but at lower are dead on. So AGAIN, set your scope at 100yds on obj lens (if it has an adj obj). Put target at exactly 100 yds, Put scope at lowest power, then POSITION HEAD AND EYE PROPERLY. Look through scope and set the rear lens for your eye( everything clear--target/crosshairs). Then its properly set for 100yds, higher powers and ranges, require adjustments accordingly as mentioned. Hope I haven't confused anyone, this has worked for me, since started trying it and using it. You will also find some scopes are better than others (less distortion/blurriness) than others at the same distances, with the same approach for adjusting/ment.


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## prairiewolf (Feb 19, 2012)

Antlerz22, welcome back !!


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## Antlerz22 (Apr 18, 2011)

Oppss.


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## Antlerz22 (Apr 18, 2011)

Short223 said:


> Another way you can check for parallax is to set up the scope, look through at a target at known yardage, set PA to known yardage and move your head up and down and side to side. IF the cross hairs move off point of aim on target, you have parallax.


Will try this to see, never noticed while I was centering my eye to scope.


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## Antlerz22 (Apr 18, 2011)

prairiewolf said:


> Antlerz22, welcome back !!


Thanks, took awhile for me to cool off.


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## Antlerz22 (Apr 18, 2011)

Short223 said:


> I understand how you are describing this. However, if your scope is set to 100 yards, and you look at a target at 100 yards,* it should be clear with the ocular adjusted completely in*. The ocular assembly is only to refine the image quality of the reticle. If a scope is blurry at a set known range, and the PA adjustment is set to that range, your scope has parallax and the ocular will not correct it.


That seems counter to design allowances, namely being to go either direction from a "balanced" and centered adjustment. Case in point, you find scope center by turning to one limit, counting clicks to opposite limit, the halving that to find dead center. Only rational design for the ocular would follow the same protocol (meaning center of travel is/should be optical center) allowing adjustment either way EQUALLY. I'm not in your camp on this one(red). If that was true, one wouldn't be able to go the other direction if needed, and that scenario certainly isn't a possibility; so far as user friendly adjusting is concerned. IMO


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