What is parallax ?

BRONCO1500

I have looked it up in the dictionary. But was somewhat not clear on the idea. Could anybody out there explain it in plain average Joe English. Thanks for any replies

Herschel

I will have to explain paralax in laymans language as I don't understand all the technical aspects of it. Here is how you can see paralax. Place the rifle in a fixed rest aimed at a bullseye or some target with distinguishing features. Then look through the rifle scope. While looking through the scope move your head from side to side or up and down. If the crosshairs appear to move across the target when you move your head, you have paralax. If the movement does not cause the crosshairs to move, there is no paralax. All scopes are paralax free at one certain range. I believe scopes designed for hipower rifles will be paralax free at 100 yds. Small bore scopes at 50 yards. The better target scopes and some hunting scopes have a paralax adjustment feature. Most frequently it will be by turning a sleeve on the objective end (front) of the scope. There will be a scale with index line to indicate the range at which the scope will be paralax free. If this is not clear email me at hsgarner@tds.net or call at 879-325-7491 and I may be better able to explain it.

Xracer

In simple (gun) terms.....parallax is the difference between your "sight line" and the "bullet line".

In other words...let's say you've got a rifle with a telescopic sight bolted to a table, exactly level. Let's say your sight is exactly level and parallel to the bore of the rifle. The difference in height between the center of the sight and the center of the bore is parallax.

Piadea

Herschel correctly describes the effects of parallax. It is caused (in simplistic terms)by the fact that the lenses in a scope are covex shaped in order to magnify the image. Due to the long focal lenght there is an optimal range at which the image will remain centered (generally 100-200 yds). At other ranges paralax will occur unless your eye is centered in the rear lens. Most high power (long range) scopes have adjustable front lenses that will remove paralax at the indicated range. Hope this helps.

easygo6

Herschel and Piadea are correct as I understand parallax. Parallax is the term used to measure (or determine) if the reticle and target appear (to the eye/brain) to be on the same focal plane. That is, does the reticle appear to be "pasted" onto the target physically. If the reticle appears to be pasted, in a parallax free focal plane, ...then the reticle will NOT move off the target simply because the shooter moves his/her eye slightly off center of the eyepiece (or ocular lens).

SEMPER FI