Jumping Frog wrote:The Annoyed Man wrote:The scope is a SWFA 5-20x50HD, and it is a superb optic. . . . It's just that parallax can be an issue in any rifle scope, . . . It's a $1,500 scope,
Don't high end scopes usually have parallax adjustment?
Parallax is often misunderstood. Here is an explanation on Optics Talk, a forum owned by SWFA, written by one of the SWFA owners:
http://www.opticstalk.com/what-exactly- ... c5026.html
Parallax
Parallax is essentially an optical illusion. Parallax presents itself as the apparent movement of the reticle, in relation to the target, when your eye moves off center of the sight picture (exit pupil) or in more extreme cases it appears as an out of focus image. It indicates that the scope is either out of focus or more specifically the image of the target is not occurring on the same focal plane as the reticle. Maximum parallax occurs when your eye is at the very edge of the sight picture (exit pupil). Even when parallax is adjusted for a designated distance, there is an inadvertent error at other distances. Most brands of scopes that do not have a parallax adjustment are pre-set at the factory to be parallax free at or around 100 yards; rim fire and shotgun scopes are set at or around 50 yards. Most scopes of 11x or more have a parallax adjustment because parallax worsens at higher magnifications. Generally speaking parallax adjustment is not required for hunting situations and is primarily a feature used and desired by target shooters. A 4x hunting scope focused for 150 yards has a maximum error of only 8/10ths of an inch at 500 yards. At short distances, the parallax effect does not affect accuracy. Using the same 4x scope at 100 yards, the maximum error is less than 2/10ths of an inch. It is also good to remember that, as long you are sighting straight through the middle of the scope, or close to it, parallax will have virtually no effect on accuracy in a hunting situation.
This is another way to think of it that maybe you can relate to. You know when you are sitting in the passenger seat of a vehicle its hard to look at the speedometer and tell how fast you are going because your eye....the needle....and the mph number are not all three lined up. So to you it looks like your going 35 when really you are going 55. But the person behind the steering wheel has his eye..the needle and the mph all lined up straight in the same focal plane and gets a true reading. Its not exactly the same thang but close enough for government work.
What most people think of as "parallax adjustment" would actually be better thought of as a focus knob—sometimes located on the back of the scope, sometimes located in a knob on the left side of the scope opposite the windage adjustment knob—which permits the user to fine tune the focus to the magnification to the distance of the target. On this particular scope, it is a side-focus knob. On my 4.5-14x50 VXIII, it is on the back of the scope, at the exit pupil. This SWFA scope has focus adjustments from zero out to 1500 yards, beyond which it is marked an "infinity symbol" (can't type it on my iPad). Either way, as the above explanation points out, it isn't entirely a matter of focus. Fine tuning the focus helps, but it doesn't cure the phenomenon. The cure is in training the operator to correctly position his/her eye relative to the scope's exit pupil (and this is why holographic sights for close up are so wonderful.....they remove parallax error from the problem of locating the target in the reticle).
In my case, the parallax issue I am experiencing on my scope is because I am having difficulty finding the "sweet spot" behind the eye piece where the image is perfectly centered in the scope, and just the crosshairs are perfectly centered over the image, but only at the higher magnification. In case you want to know what 20X looks like, it makes something that is 1,000 yards away look like it is only 50 yards away to the naked eye. This parallax effect is maginified at highest magnification, and minimized at lowest magnification. Thus, the problem is me, not the scope. And, this type of problem is common to high magnification scopes, regardless of brand. That is not to say that everyone will experience it at high magnification, but some do, and I'm one of them. I regard it as a matter of training.
“Hard times create strong men. Strong men create good times. Good times create weak men. And, weak men create hard times.”
― G. Michael Hopf, "Those Who Remain"
#TINVOWOOT
I'm getting old. 
Due to some genetic & physical issues that my son has it is likely that we'll never be able to share this experience. But, we do lots of other fun things together. And my girls will get to learn as much about firearms as I can teach them (or pay to have them taught).
