Anyone see this with their scopes?

[callgood]

I've had a Bushnell 3200 for a year or so. I noticed that when I look thru it with the horizontal reticle level, the bottom vertical reticle is slanted a bit- doesn't hit "6 oclock." Not much, but I can notice it.

So I just mounted an IOR Valdada and- same thing. Again, not much, but I can tell.

Last night I got the Bushnell out and mounted the rifle left handed. When I look thru the sight with my left eye, same thing, only the reticle slants the OTHER way- left I think.

Do I need to line up a cane and dark glasses, or what?

[griz]

Use some sort of grid with perpendicular lines to check the alignment of the scope mount. (maybe a cinder block wall?) But unless the two companies conspired to sell you scopes with a plumb bob misalignment system, the problem is the way you are holding the rifle.

[LHB1]

Callgood,
Do you wear eyeglasses? The symptom you describe sounds like curvature of field. It is often seen in binoculars, spotting scopes, AND eyeglasses due to the curvature of glass and angle of light diffraction closer to the edge of lens. It can even be caused by irregular curvature of the eye, or so I have been told.

Good shooting and be safe.
LB

[CB900F]

Fella's;

A large number of scope makers now etch the stadia onto a lens I'm told. Hard to believe that you'd get a curved crosshair in a scope using that method, which I think the Elites do.

900F

[LHB1]

900f,
You didn't understand my post. I did not say the crosshair is actually crooked. The phenomenon of curvature of field means that the "image" of the crosshair gets curved as it passes thru the lens on the way to your eye.

Good shooting and be safe.
LB

ps: This definition from Leupold website doesn't really explain it well but:

The Leupold Answer Guide

What is the curvature of field?
Curvature of field is len aberration that causes a flat object surface to be imaged onto a curved surface rather than a plane.

[CB900F]

LHB1

Aw contrary there misterseur, mercy buttercups, silver plates & all like that there.

I was speaking to Callgood & pointing out that it's highly unlikely that the stadia in his scopes were actually not straight & perpendicular. I have no problem with your reasoning however.

:D 900F

[LHB1]

900F,
My apologies for misunderstanding your post!

Good shooting and be safe.
LB

[callgood]

Easy enough to test. I'll take my progressive lens off and try it again. That sounds likely, since the curvature of the left lens might make it the lower vertical reticle slant one way, while the right lens causes the opposite illusion.

I'll let you know if that solves the problem- or not!

Thanks to all,
callgood

[JackOfAllTradesMasterAtNone]

Yes, An optical illusion.

So really, there's no problem.

And now that you've dismounted and remounted scopes on rifles, you've got a good reason to go shooting again. To sight them in.

-Steve

[Double Naught Spy]

It isn't a problem unless you use that part of the scope and the hair's alignment for some purpose. Then, the optical distortion is a problem.

Note, it is not just an illusion of being an image of something not there, but the illusion is the product of the image being distortion via lens refraction. There are all sorts of optical illusions, many of which are not the product of the image being distorted, but the play of color, scale, size, and shape, sometimes of misdirection. You can have illusions without the true image being changed. In optics, when the image is manipulated in a manner where it is no longer correct, you have distortion.

I suspect that in the case here, the distortion is along the edge as created as a result of perspective and lens curvature. As with most household magnifying glasses, the middle may look fine but the things seen around the edges are blurred or take on changed shapes such as curvature. There are lenses that are ground to preclude such distortion, but the angle of viewing is still critical. It doesn't seem possible to have a lens through which the image is not distorted when viewed from any angle, but the image should not be distorted when seem from the proper angle.

[degen118]

I have seen this problem with the cheaper scopes. I juat picked up a Carl Zeiss, and it is clear from edge to edge as the saying goes. Just my 2 cents.

[callgood]

LHB1 nailed it. I put the Bushnell back on and mounted the rifle, right handed. I lifted my eyeglasses and, bingo, the lower reticle moved (if it was the minute hand on a clock) from 27-28 minuter after to 30 minutes after. the effect is less pronounced if I mount the rifle left handed, but the results are the same.

As someone said, if the reticle isn't being used for some purpose, it's no big deal, but I'm glad I can explain it. Thanks for the input!