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/...Some claim parallax problems at close range, but I haven't noticed any while using them on my .22s which I usually zero at 50 yards. A K4 on my Remington 550-1 (my personal favorite .22 rifle):
Most shooters really do not understand parallax error.
Parallax error is caused by the image produced by the lens system being in a different focal plane than the reticle, when the eye is not in the optical center of the lens system.
The amount of parallax error that occurs depends on:
- the distance between those two focal planes;
- the amount of magnification;
- how far off center your pupil is from the optical center; and
- how far the target is from the distance where the scope is adjusted for no parallax error.
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To put that in practical terms:
The higher the magnification the greater the parallax error as the light is being "bent" more to create the magnified image and it creates a greater difference in the focal plane.
In addition, the higher the magnification the smaller the exit pupil and the greater the effect of having your eye slightly outside the optical center of the lens system.
As a result, low power scopes in the 1.5 to 4x range just don't demonstrate much parallax error compared to an 8x, 9x, 12x 16x, etc scope. Back in the day you rarely saw an adjustable objective lens on a 3-9x or lower power variable scope. That was because 9x was the point above which parallax error really starts to be a big issue. For the same reason, you rarely saw a scope that had a maximum power of more than 9x that
did not have an adjustable objective lens.
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Fit also matters. In order to minimize parallax error the rifle stock needs to fit you well enough to place your eye so that it is centered horizontally in the center of the cone of light produced by the scope. The scope also has to be mounted at the right height so that your eye is vertically centered in the scope as well.
Even if a scope has a lot of *potential* parallax error, if your eye is always in the optical center of the scope you won't have any parallax error.
Similarly, but a lot less ideally, even if your eye is outside the optical center of the scope, but is *consistently* in the same place for every shot, you'll have parallax error, but that error will be consistent and you can still shoot good groups.
Remember, even if the eye is off center, the closer your eye is to the center, and the lower the magnification, the less parallax error you will have.
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How the scope is set from the factory also makes a difference in the amount of parallax error.
Most non adjustable objective or non "side focus" scopes that are made today and are intended for centerfire rifles have the parallax error set for 150 yards. Most rimfire scopes are set at the factory for 50 yards.
Back in the day scopes like the K4 were factory set with a zero parallax distance of 100 yards. That's a plus for a scope that will be used on a .22 LR rifle at 25-100 yards, compared a scope set for 150 yards. The low 4x magnification also greatly reduces the parallax error and the generous objective diameter for the power produces a large exit pupil.
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You can see for yourself the magnitude of parallax error at any given distance. Set you rifle securely on bags or a bipod and rear bag a align the cross hairs on a target. Then, without moving the rifle, move your eye slightly side to side. As you move out to the side to where you can still get a full field of view, you'll see the cross hairs move on the target - unless you are at the distance where the scope is adjusted to be parallax free. The farther you are from that distance, the more error you will see, and the farther your eye moves from the center, the more error you will note.
If you have a scope with a parallax adjustment (either on the objective, or a side focus knob) you should do this same test to verify the adjustment is accurate. It often isn't, even on high end scopes.