Got a beef with "parallax"

[bigbadwulff]

Coming from an optical background I have a slight beef with the term parallax and how it is used.
If you are talking about the effect of the rifle barrel pointing from one direction and the scope viewing from a slightly different direction, then THAT is parallax.
If you are talking about viewing thru the scope and moving YOUR position relative to the scope optics and the image moving that is..................... prismatic effect.

Let the discussion commence

[SuwanneeDave]

The word is commonly accepted as the second meaning when dealing with scopes.  It may not be optically precise but many words acquire a commonly used meaning within a certain context.

[bigbadwulff]

I completely understand.

But thought I'd throw it out for the general informational education of the masses

The line of parallax does not change(unless the scope moves ......or the barrel). Prismatic effect changes the more you move from the optical center of the optical system.

Now don't get me started with entrance and exit pupils and cardinal points....because, well everyone forgets that as fast as they can and few(me not included)) ever grasp the entire concept.

[Rickster]

You seem to be quoting the definition from the dictionary.
I think Parallax applied to rifle scopes is a little different.
It is explained pretty good here.
http://www.6mmbr.com/parallax.html

You can check the parallax of any scope by sighting an object at normal shooting distance (not indoors), by moving your eye side to side (then up and down), as far as you can, keeping the sighted object within the field of view. The apparent movement of the reticle in relation the target is parallax.

Rick