Visual distortion of target

[memilanuk]

So... at the range today, and ran smack-dab into something that has been bothering me for a while now. Certain types of targets (specifically, the round BC Shoot-N-C targets with the bright orange dot in the center) seem to just give my eyes fits - as in when I look thru the scope, it looks like the dot is *not* in the center of the inner ring, but offset. Today was really bad - it looked like the dot was literally touching the ring @ 12 o'clock. Needless to say, that gave me some concern about where to aim - where I think it should be, or where I actually see it as being.

I'm reasonably certain this *isn't* simply mirage. I think I've shot enough that I have a pretty fair idea what mirage looks like, and how it behaves. I'm not seeing the *whole* target distorted, or wavy - just that center orange dot. If I look at some other type of target, say an Orange Target Spot with the black diamond in the middle - no problem. Everything looks centered up. Same goes for a regulation F-Class center - everything looks fine... other than the lines being too dang fine, but thats not a distortion issue.

As indicated at the beginning, I have noticed this for a while now (couple years at least) to varying degrees. With my NF 12-42x56 BR or NXS @ 42x, its sometimes noticeable (usually I'm shooting @ 300yds when I notice this, at two different facilities). With my NF NXS 3.5-15x50 or 5.5-22x50 it is very noticeable - especially with the 3.5-15x. Today I was using a Weaver 3-15x50 FFP mil/mil scope and it was the worst I've seen yet.

I'm familiar with the problems of looking thru the corner of your eye-box, especially with prescription glasses (which I normally wear). Today I hopped back in the truck and put in some disposable contacts - then the problem was much reduced, albeit with the dot now looking like it was slightly *below* center instead of way above. I know I have a slight amount of astigmatism - but never enough that the doctors have wanted to prescribe contacts specifically corrected for it. Might be its time to go have another talk with them about the matter?

The part that just baffles the crap out of me, is why it just jumps out at me with certain colors/shapes and not with others? We have a display screen on a generator control @ work that has a graphic that is a series of concentric circles with bright contrasting colors for the center and at any where other than right in front of it about a foot away, it looks distorted off-center like I see those Shoot-N-C targets with the orange centers. Yet most other target styles/colors I don't even notice it.

Anyone else experienced this, or have any idea why it would seem to relate to specific colors/shapes? Luckily we don't shoot for score on those dang Shoot-N-C targets or I'd really be screwed... :-\

Monte

 

[artbosco]

First things first. When was the last time you saw an Optometrist or an Ophthalmologist?

 

[dmickey]

Is the lens of your scope clean? No finger smudges on the lens?

 

[memilanuk]

First things first. When was the last time you saw an Optometrist or an Ophthalmologist?

Twice at least, in the time frame that I've been noticing this. About a year and change since the last one.

Is the lens of your scope clean? No finger smudges on the lens?

Yes. Gimme a little credit, eh?

 

[necchi]

There can be several factors, diet, medication, age,, it's endless to the laymen and it IS all science friend.
All of us develop some color blindness as we age. I don't think what you have is color blindness, it's a shade sensetivity thing.

If you look at this link and read it you might nderstand some of it. About halfway down there are 8 circles for a color test, in four of them I can't see the number??
http://micro.magnet.fsu.edu/primer/lightandcolor/humanvisionintro.html

Some targets give me fit's also, theres a bunch of free printable targets all over the web and I've picked through many finding ones that work best for me and load testing. I never really cared for the shoot-n-see, they're fun for kids at 25-50 yrads but worthless for actual distance sight in or load work, after the first 5-6 shots the whole damn thing is a yellow blob. And they cost alot.

I use a 2" black square with a dime size circle of white in the middle. I can see that dime size dot at 200, and the black square at 300.

 

[memilanuk]

Nope, definitely not color-blind (used to do electrical work, kind of a non-starter being color-blind in that job field).

That document is a bit further down the rabbit hole than I was wanting to go I'll give it a go at some point, though.

The biggest reason I started using the Shoot-N-C targets was to be able to see bullet holes at distance - lighting angles at some of the local ranges are not conducive to seeing holes with a rifle or spotting scope.

As for the expense... they do come with pasters, and you can buy packs of 'em to. I can make one target face last quite a while with those.

 

[Flybuster]

Hi Monte,

If you get a chance have someone else look through your scope at that same target, to see if they are seeing the same distortion. That may help narrow it down.

 

[Keith Glasscock]

Let me guess, 3" shoot and see? I use those too. They make a great substitute for the F-class 10 ring...

Here are some ideas. I bet you've already considered most of them...

Was it by chance a little misty or foggy? Certain colors have a tendency to distort more through fog/mist than others. I think the term is chromatic abberation - some colors focus at different distances through a series of lenses. In the case of fog/mist all kinds of funny stuff can happen depending on the angle of the light.

I also get some funny stuff going on when I am near the edge of the lenses of my glasses, but it looks like you have already considered that.

Does it happen through your spotting scope? I have varying degrees of weirdness with different scopes. It could be a matter of lens coatings.

I also have seen some really weird stuff due to lens flare on my Leupold. I have to run the lens shade all the time.

Better yet, don't worry about it - I need every advantage I can get ;D

 

[memilanuk]

Let me guess, 3" shoot and see? I use those too. They make a great substitute for the F-class 10 ring...

More like the 12" one with the 3/4" dot in the center. The dot reticle on my scope fits inside the dot on the target @ 300yd with a nice even ring of orange around it... the black diamond on the orange Target Spots is too easily confused for the dot in the reticle...

Was it by chance a little misty or foggy?

No, not really. Usually a reasonably clear (i.e. no haze or fog between the firing line and the target) although some times it may be heavy overcast. Other times its been nice bright n sunny with light directly on the target (at the other range across the valley).

Does it happen through your spotting scope?

Ya know... that I can't say for sure. I don't *think* so... but I can't swear to it. Then again I'm usually looking straight at the lens of the spotting scope (45 deg eyepiece on a Kowa 821M) and not out of the corner of my eye or thru the edge of my glasses....

I have varying degrees of weirdness with different scopes. It could be a matter of lens coatings.

That was my first thought yesterday - the scope in question was a new Weaver 3-15x50, FFP, illuminated EDMR (mil-hash) reticle, 1/10 mil clicks, etc. Nice scope for the $$$, but its only half what a NF NXS 3.5-15x50 costs new so they had to cut some corners somewhere. But up until yesterday, the NXS 3.5-15x had been the worst offender, followed by the NXS 5.5-22x; on the 12-42x BR and NXS scopes I have it was just noticeable. But when I took the glasses off and put the contacts on, the effect changed/shifted... which seems to indicate (to me) that while it may be affected by some relation between the scope lenses and my prescription lenses... the scope(s) may not be the major culprit. Unfortunately I no longer have the NXS 3.5-15x and 5.5-22x to test against...

 

[Greg110]

Go back to what the Outdoorsman and Busdriver have said. Eyeglass lenses do not have the same correction in all meridians. That is just eyeglass optics. Best thought is to see an eyeglass fitter that will make you a pair of "shooting" glasses with the optical center located so that you are looking through the optical center while you are in shooting position. Of course, that means finding someone who is "gun friendly" enough to do the work. And stay away from lenses with aspheric curves if you can. That just worsens the screwy effects of astygmatism and off center.

 

[Keith Glasscock]

I've been playing with the idea of buying some new prescription lenses for my Decot Hy-wyd frames (used to be a shotgun guy). I know they will put the center wherever you want...

 

[memilanuk]

I just ordered some new plano (no scrip) lenses for my Hy-Wyds. Normally I wear contacts when I wear those... but my lenses got scratched all to heck last summer. I may have to try some prescription lenses for the Hy-Wyds... luckily the optometrist I use *is* a competitive trap shooter so he understands what I'm talking about. I've avoided prescription safety/shooting glasses up to this point... my regular glasses are not cheap (5.00 correction with ultra-light hyper-index lenses, anti-glare coatings, titanium alloy frames, etc.) plus contact refills. Fortunately, my correction doesn't seem to change real often so hopefully that'd soften the blow of new prescription lenses for the Hy-Wyds.

 

[ratguner]

Monte, My first impression was that you went back to iron sights.
Contacts float on your eye, so you can not be positive that the lens is centered on your cornea. Have you tried to scope the target without any glasses?

 

[memilanuk]

I could *almost* get away with it... the +/- diopter adjustment on the rear ocular isn't quite enough.

 

[Greg110]

I "assume" that you're wearing soft contact lenses. I have found that I get noticeably higher quality vision with gas perm lenses. I am wearing one of the hyper Dk materials and, for my shooting lens, I had it fit a little tighter. So I could see the irons, i had it made with less minus (kind of like the intermediate seg on a tri-focal). Once I got everything sorted out, the front sight is real clear and the target not too blurry so I am pretty happy with the results for my 65 yr old eyes.

 

[memilanuk]

Greg,

Yes, when I wear contacts lately they've been disposable soft lenses. I know they have a certain amount of +/- to the production process that may vary from lens to lens. When shooting irons its usually close enough (for me) to where I can get by with a front lens and just tweak the rear aperature a little. Now that front and rear diopters are allowed, I might try a rear lens again just to see if I could fine tune things a bit. To be honest, that wasn't what was holding back my iron sight shooting as much as just lack of practice.

At any rate... I don't know that would distort just one color...?