i'm abit confused about the differences of AO and fixed objective. and by that i mean what advantages would having a fixed objective scope be. i see that many or most scopes without AO are fixed at 100 yards. if i had an AO scope of similar specs and just left it at 100 yards, would it be the same? what would the differences be between the fixed objective at 100 yards and the AO set to 100 yards? i have a bushnell sportsman 3x-9x 32mm AO and when the AO distance isn't right, the thing i'm looking at is blurry. i assume this isn't the case with fixed objective, and thats why people use them? or are fixed objectives also blurry the further or closer you get from the distance its fixed at?
need some clarification on AO and fixed objective
- Thread starter SSJChar
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sillymike
CGN Ultra frequent flyer
The AO is used to adjust the Paralax (http://www.6mmbr.com/parallax.html)
If you have a "perfect" shooting position, and always put your head at the exact same place on your stock, with the exact same cheek pressure, at the exact same distance of your scope, looking thru it at the exact same angle... parallax won't be much of an issue (For the rest us, we use AO)
Scope with no AO are adjusted/buillt to be free (pretty much) of parallax from a distance of 150 yards or more...
If you have a "perfect" shooting position, and always put your head at the exact same place on your stock, with the exact same cheek pressure, at the exact same distance of your scope, looking thru it at the exact same angle... parallax won't be much of an issue (For the rest us, we use AO)
Scope with no AO are adjusted/buillt to be free (pretty much) of parallax from a distance of 150 yards or more...
I find my scopes with AO are far more prone to being out of focus than the fixed objective scopes. I can take a fixed object scope and look close or far, and the target is in focus. If the AO was set at 100 and I looked closer or further, there would be pronounced out of focus. So for hunting, I'd say fixed objective is my preference.
AO has nothing to do with focus. It is only to adjust for parallax effect. Parralax is the efect you can see when at longer distances (200yrds +) where when you shift youre eye side to side while looking at your target you see the crosshairs move across the target. Adjusting for parallax, means that if your eye position relative to your optics is not always 100% (as is rarely is) you will still be on target. Focus is completely seperate and has nothign to do with focus whatsoever. (read leupolds website explanation of parralax.)
Cheers
Cheers
drvrage, I agree that parallax and focus are separate issues, but do you not observe that with AO scopes the image (not the reticle) is out of focus when set to distances closer or further than the distance to which they are set for parallax? If I set my AO scope up for 150 yards no parallax then aim at a target at 75 yards, the target is visably blurry. Much more so than my non AO scope. And when I then adjust the parallax setting to 75 yards, the image comes back into focus. I have only two AO scopes, but both are that way. Only sharp in image focus when adjusted for parallax. I'm not saying that the two settings, zero parallax and sharp image coincide precisely, but they appear to closely. Not your experience?
TackAttack
Member
- Location
- Calgary, Alberta
I agree with sillymike and grizzlypeg, my preference is no AO for my hunting rifles but like the AO for benchrest. I find that objects are parallax free from @100m to infinity on no AO scopes depending on the magnification.
The error that may be caused by parallax (eye not consistently positioned on scope) isn't significant enough to cause problems with hunting at 6 yards. We are generally talking about very precise shooting and the error that is induced by inconsistent eye placement. So this will concern target shooters and someone shooting at small game like rodents at significant distances.
