Optics: Parallax vs Focus

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Paradise Re-gained

I recently had Cataract Surgery in both eyes. The first thing I did the morning after the surgery on my "Shootin Eye" was re-focus the reticle in the 6X scope on my RF Sporter. Dang! Paradise, re-gained, indeed. When one can see the irregularities on the reticle hairs, they are HOME :D

Prior to this, I could not keep the reticle focused no matter what I did. Not long ago, I saw an ad on a Bass Fishing show for Clear Eyes or some such name. The gest of the ad was no one has to suffer with not being able to see and if one wants to pursue a sport that requires great vision, one might consider getting this "Clear Vision", which I think is having one's eye ball lenses replaced with lenses that work. After having mine done, because of cataracts, I would not hesitate to get new eyeball lenses if that would correct my vision to the point that I wasn't hampered by vision problems.

I waited to get my Drivers License renewed until after my surgery. I wanted to get the glasses restriction removed if I could. I wet to the DMV office last Thursday and renewed my license. The clerk tested my vision and when finished she said" whatever you had to pay for that was certainly worth it. You are no longer restricted to wearing glasses when you drive. This gave me a new "View" of getting the surgery, even before cataracts, providing it is possible.

Pete
 
Pete,

Thanks, I read that article. Fresh info for me about side focus AO backlash.

So it seems to me that, if the ocular is not adjusted to truly focus on the reticle plane, and the parallax has been removed, the image at the zero-parallax distance will be blurry.

By definition (according to the various reference material and comments): If there is no apparent movement of the reticle against the target, then there is no parallax error, and the image is focused on the same plane as the reticle.

So it follows that, if above condition is met, yet the target appears blurry, then the ocular is not perfectly focused on the reticle plane.

Then it follows (correct me if I'm wrong) that one way to focus the ocular in this scenario could be to make quick looks at the target (rather than the reticle itself) and make incremental changes in the ocular until the target image is clear at first glance. (Again, this assumes the target image is truly focused on the reticle plane.)

Comments?

Brian
 
For your eye and any corrective lenses that my be in use, there is one occular setting that will focus the eyepiece in the plane of the reticule, the focusing of the target image is done with either an adjustable objective, or side focus. If you have peak target image sharpness and no parallax, your eyepiece adjustment is correct, for you. Repeating my earlier posts, if a sharp target and zero parallax are not at the same point of objective or side focus adjustment, you will need to make small changes in the eyepiece setting, and refocus on the target using either the side focus, or adjustable objective, every time that you move the eyepiece, and then check for parallax, repeating until you get both at the same setting. For this part of the adjustment, a quick glance is not needed, and offers no advantage. That is just for the initial focusing of the eyepiece on the reticule, where there should be nothing in your field of view to draw your eye away from the reticule. (open blue sky, ceiling too close to focus on at the magnification that you are using, white paper held up a foot or two in front of the scope)
 
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Boyd,

That's exactly why I asked the question - to elicit a direct refutation if one was forthcoming. Sorry if it was redundant. I finally have all the information I need to tackle this adjustment.

Brian
 
If you have a 6-20x scope adjustment at any given power in between those extremes should not change the adjustment of the eyepiece for focus on the reticule as you go up or down in power. Is that a correct assumption?
 
Correct. Your sole task with the eyepiece is to get it focused in the plane of the reticule. This is not to say that the objective or side focus will always be the same at different magnifications of a variable scope, but that is easy to test, and adjust for, because, if the eyepiece focus is correct, all you have to do is adjust for your sharpest target image, and you should be good to go for that and parallax as well.
 
I thought so but wasn't 100% sure. I have a Leopold VX-2 6-18x due today and that knowledge will help getting that Duplex in focus...should be easier than the fine cross hairs on the Weaver T-36.
 
Maybe just because it's Friday, but:

Why do some of you say "reticule"? A "reticule" is a small handbag for carrying embroidery etc. All the optics manufacturers refer to "reticle."

[Flame suit on. :eek: ]
 
It's like with casting bullets. Some say spruce, some say sprue....same difference to me. Of course, the latter is correct. It also depends on your spell checker and if you choose to believe it.
 
Don't confuse me with facts.

"A man convinced against his will ..."
 
But back to the subject at hand ...

Which eyeglass prescription do most of you use at the bench? Would a "reading" prescription be better than "driving" one? Seems to me it would be. After al, we are not trying to focus on 100 or 200 yards, we are focusing on a reticle plane a few inches away from our eye.

Brian
 
I'm a bit near sighted and while I don't use glasses while at the computer, I need it for watching TV and especially driving and trying to see a target via the scope at 100 yards. My bifocal part of the glasses would be useless for me trying to see that target.
 
I am nearsighted and have no trouble using the upper part of my bifocals when shooting. The eyepiece is designed to focus on the reticule, and has sufficient range of adjustment for most to accomplish this using lenses that are designed for normal distance use. In my limited experience, those who are near sighted (need glasses to see sharply at a distance) will be turning their eyepieces in from center, and I would assume (perhaps incorrectly) that those who are far sighted might find their proper eyepiece focus going in the opposite direction. There is no easy or hard, either you can focus the eyepiece so that it is focused exactly in the plane of the reticule, or you cannot. (again, my opinion) Because I need to be able to see wind flags with my off eye, I would not want to wear reading glasses for shooting, and because the reading portion of my bifocals are placed low in my lenses, looking through that part would not work.
 
Brian--Reticule is also correct. I have old gunbooks and scope manufacturer's books that spell it that way.
 
If you look in any of Jack O'Connor's books on rifles he spells it reticule as well. A master's degree in journalism and life long writer should know how to spell it. It's like the word "befor". I've seen it spelled with and without an e at the end.
 
Brian, also graticule, not to be picky BUT, using reticule VS reticle isn't like saying "Kelby's" or "Hornaday" or misusing Their/there/they're or two/too/to or the very common "gaulding" and "spaulding" for galling and spalling.............. because all the words (reticle, reticule, graticule) are CORRECT

:)


al
 
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