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AO and Parallax

430 Views 10 Replies 4 Participants Last post by  TheOpticZone
I'm confused about adjustable objective, variable magnification, and parallax settings. Do you need an AO to focus images on a variable magnification scope? Are "adjustable objective" and "adjustable parallax" the same thing?
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The stickey at the top of this section "setting up a new scope" explains it a little. After reading the stickey if you still have questions let us know.
 

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Discussion Starter · #3 ·
Thanks. I read the sticky. I'm still confused about scopes with adjustable objectives and adjustable parallax settings. Is an adjustable objective the same feature as adjustable parallax? i.e., Could you find a scope with an AO, but without adjustable parallax?
 

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Testman,

An adjustable objective and side parallax adjustment do the same function. The adjustable objective is on the end of the scope on the objective end, where as the side parallax adjustment is done on the side of the scope (Knob on the side, by the turrets). More and more scopes are going to the side parallax adjustment due to the ease of adjusting without moving your head and the image in the scope. Scopes with potential parallax problems and high power scopes with either have an adjustable objective or a side parallax adjustment, never both.
 

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testman said:
I'm confused about adjustable objective, variable magnification, and parallax settings. Do you need an AO to focus images on a variable magnification scope? Are "adjustable objective" and "adjustable parallax" the same thing?
Whether the scope is a variable power or a fixed power really has no bearing on whether is has an AO. And "Adjustable Objective" & "Adjustable Parallax" both accomplish the same thing. When you look through your scope you are not really seeing the target, you are seeing the image of the target projected on a plane inside the scope. The reticle (crosshairs) are also on a plane inside the scope. If the image & the reticle are not on the same plane you will have some parallax. (Which means the relationship of the target & reticle will change depending on where you place your eye behind the scope.) The AO allows you to move the image to the reticle plane & at the same time provides you with a better focused image. Most all "Deer Hunting" scopes are set to be parallax-free @ 100 yards or greater but most .22 shooting is done closer to 50 yards. If you are going to use a .22 for target shooting, and especially if you are going to be using a fairly high magnification scope be sure and choose one with the AO (or AP).....
 

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Discussion Starter · #7 ·
Okay. I confused myself again.

How do you focus a scope that has a fixed parallax setting? Would you have to adjust the eye piece/reticule lens? Or are you not able to focus the target's image at all?
 

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testman said:
Okay. I confused myself again.

How do you focus a scope that has a fixed parallax setting? Would you have to adjust the eye piece/reticule lens? Or are you not able to focus the target's image at all?
You use the Ocular (eye piece) adjustment on any scope (AO or non-AO) to focus on the reticle (crosshairs). This is best done by pointing the scope at a clear blue sky. And just look through it for a very few seconds at a time. If you look long enough your eye will adapt. You want it focused so that the instant you look at it the reticle it is sharp & clear.
 

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TheOpticZone said:
With a fixed parallax setting, you get what you get. Your eye will need to do the focusing.
TOZ, I'm sure you are aware, but Testman may not be: The function of the AO goes way beyond just focusing on the target to get a clearer image. If there is parallax, unless you position your head in exactly the same place every time you look through the scope (& none of us can!), the relationship of the reticle to the target shifts. This can seriously effect your point of impact on the target.
 
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