What are Ghost Ring Sights?

[canucklehead]

Sigh. Your eye is an optical system. I think this is pretty well scientifically established.

As mentioned, please consult an opthamologist (sp?). He will show you the error of your ways, or report you to the authorities for being a mutant.

"I should add at this juncture that I am not saying that I can see a distant object in as much detail as I can a closer one, I cannot. What I am saying however, is that when I see an object in the distance, that object does not become less distinct due to the presence of, or to my attention to, a front sight when viewed through an aperture rear sight."

Wow. Complete contradictions within the same paragraph. I fear we are at an impasse... this will be the last post, as obviously your knowledge of optics exceeds that of the scientific community.

 

[Boomer]

There is no contradiction at all. Seeing detail at distance has to do with the percieved size of the object, not with focus. For example, a paper target can be seen in focus from 100 yards. Yet the staples holding that target to it's backboard cannot be seen at that range - this has nothing to do with focus.

When the target is viewed through a rifle's aperture rear sight, and a post front sight is held at 6:00, the portion of the target which is visible remains in the same focus as it was prior to aiming at it.

 

[jaycee]

if you take a picture of a fox head on, it's eye might be in sharp focus, but everything behind it's shoulder is out of focus. This is because the camera lens compresses distance, but the eye does not. Interestingly enough camera lenses increase their depth of field by adjusting their F stops - which is in effect an aperture inside the lens body.

Part of your misunderstanding probably stems from your misunderstanding of camera lenses. Your example of camera lenses compressing distance is only true if you're using the lower F stops - use higher F stops and you will get great field of depth; distant objects will be very close to focus as well. In fact, even at the lower F stops, in my experience with photography, the shoulder would not be all that out of focus due to the short difference in distance - something a few feet behind the fox would be out of focus, but the fox itself would predominantly be in focus. The aperture in the camera lense you are speaking of is called an iris, because it does pretty much the same job as the iris in the human eye.

jaycee, I am only talking in circles because you are refusing to accept what I tell you, so the discussion is likely to go round and round adnauseum. But fear not, I will continue to try to get my point across.

No Boomer, it is you who is refusing to listen; you disregard hundreds of years of medical research, because apparently you know better than all the doctors, opthomologists and optometrists in the world. Like I said before Boomer, talk to an opthemologist or an optometrist - but I'm sure you'll just ignore this suggestion just like you've apparently refused to both do, and discuss on this forum to date.

No Boomer, for you I fear this has gone beyond having a rational discussion about this - if the correct answer came up and slapped you on the head, you'd probably still deny it.

Range finding is very much the point of the discussion. I think we agree that we can focus on two objects side by side at the same range. I can assure you that when the normal benchmarks we use to estimate range are removed from our vision, all distant objects visible appear to be in a single focal plane. Only if we can be certain that the two objects are of similar size, can we then deduce that the one which appears smaller is actually farther away. This is why the post and front sight analogy works. The only way your argument can stand up is if you can be sure that the two objects are in fact at different ranges. Because the eye has such a long depth of field, we are pretty poor at estimating range - particularly when the common indexes we depend on are not there.

I would disagree here as well. I too have spent a lot of time in the snowy north - in fact a good part of it in the same neck of the woods as you - and yes, on a featureless expanse such as ice or flat tundra, it can be difficult to estimate range, it is still somewhat possible; ie. I may not be able to tell exactly what range an object is, but I can readily determine if there is a large difference in the distances (I can tell the difference between a seal at 30 yards vs. one at 200 - something you didn't respond to in the last post). As someone has already alluded to, the distance between your eyes is basic range finder - look at the older type of artillery rangefinders - they are basically a pair of binoculars with the ocular lenses about 4' apart - so they can accurately range objects miles away. Human eyes aren't capable of the same accuracy, but they are still able to tell if something is closer.

Once an object is in your far field focus it remains in focus, until you are distracted by an object in your close field focus, or in your peripheral vision, which I would define as what you see on the outside edge of your normal vision. This would most often be to your left or right, but it could also be above or below you, but it would not be off in the distance. You cannot focus on objects in your peripheral vision, you can only be aware of them, that is until you focus your attention onto them. Once you focus on these new objects which are now centered in your normal vision, the objects which you had focused on are now on the periphery of your vision, so you can only be aware of them but would be unable to focus on them.

Last time I checked, nobody was arguing this, Boomer.

When we look through our ghost ring rear sight, we are adjusting the width and breadth of our normal vision to a very narrow path. It would be very difficult to observe objects in our peripheral vision when looking at the front sight through an aperture. For this reason when the shot is being made on a live target it is preferable to keep both eyes open - but this is not possible for everyone.

Again, nobody is arguing this. What's your point?

As long as we look through that aperture, the front sight will provide us with a sharp and precise index of where our bullet will strike our in focus target.

Except for the little point that our target won't be in focus if our front sight is, and vis versa.

I should add at this juncture that I am not saying that I can see a distant object in as much detail as I can a closer one, I cannot. What I am saying however, is that when I see an object in the distance, that object does not become less distinct due to the presence of, or to my attention to, a front sight when viewed through an aperture rear sight.

Then perhaps your vision has degraded to the point where your target and front sight are both equally out of focus, and thereby appear to be equally "in focus" to you. Maybe you should go see an optometrist and get your eyes checked; if nothing else, you could have the discussion you keep ducking. I'm sure the optometrist would be interested in getting a lesson from you about how the human eye works.

 

[Can-down]

I think the comparison to a camera's iris is a good one.
Smaller iris (aperature) gives better depth of field just like a small peep sight (not a ghost ring) gives your eye a better depth of field and makes it easier to see the target and the front post clearly.

All this talk made me pull out a rifle with peeps and compare the difference looking through the peep at the front post on a target and looking beside the peep at the front post and the target.

I don't know if both are in perfect focus but I can see that post and the target much clearer when looking through a narrow aperature.

 

[jaycee]

I don't know if both are in perfect focus but I can see that post and the target much clearer when looking through a narrow aperature.

And this is exactly as should be expected. If one looks at a set of Full Bore aperture sights - commonly used to shoot out to 1000 yards - they have unGodly small apertures, because the small aperture sharpens up the sights and target, just like it improves the depth of field in a camera lens. Unfortunately, they are all but useless on a quick shot, which is where the ghost ring aperture really shines.

 

[Boomer]

So now we come around to the original premise - is the front sight and target in focus at the same time? Can-down at least has taken the initiative to pull out a rifle and try it, and seems to think that if there is a difference between the sharpness of his front sight and target he is unable to detect it. Perhaps that is the situation for me as well, but then that is my reality - my front sight and target are in simultaneous focus.

If using a peep sight produces a greater depth of field that a ghost ring, then a ghost ring must produce a greater depth of field than normal vision. Perhaps this helps explain why my front sight and target are both in focus - despite opinions to the contrary. I know that the target would not be in focus if I was aiming with with open sights.

jaycee - In the light conditions I have described, you might be able to tell the difference between a seal at 30 yards and one at 200, but you would be hard pressed to tell if the seal at 30 yards was at 30 or 100 yards. You cannot determine the difference between a seal at 100 yards and one at 300 yards in the light conditions I have described, without knowing the relative size of the seals in question - and there can be huge differences in size. Without the aid of technology (such as your very handy Barr and Stroud) or without the normal indexes we use to judge distance, we are lost.

You might of hung around up here for a while, but unless you've been out on the sea ice in flat light you have no clue what I am talking about. The tundra is easier, although at times not much, because there are willows, grass and rocks to aid in our depth perception. On the sea ice in flat light, without colored glasses you cannot focus on the ground directly in front of you, you cannot see drifts, and you cannot see pressure ridges, unless there is enough light that they appear green. Ranging an animal or object of unknown size under these conditions is all but impossible. You know that your front sight is 30" from you eye, but if you don't think about that, it could be a dark post hundreds of yards away as far as you eye is concerned. If you observed a dark post hundreds of yards away and laid your front sight beside it, and both appeared to be the same size as you aimed through your ghost ring, each one would be in focus.

Now, if we return to normal light conditions, and the topography gives us a 3 dimensional view, should we encounter a similar arrangement with a target post alongside your front sight, the front sight and the post will still appear in focus.

 

[jaycee]

So now we come around to the original premise - is the front sight and target in focus at the same time? Can-down at least has taken the initiative to pull out a rifle and try it, and seems to think that if there is a difference between the sharpness of his front sight and target he is unable to detect it. Perhaps that is the situation for me as well, but then that is my reality - my front sight and target are in simultaneous focus.

Boomer, perhaps you should read Can-down's post:"I don't know if both are in perfect focus but I can see that post and the target much clearer when looking through a NARROW aperature." Nobody's been arguing what small apertures do Boomer, or maybe you missed that. We're talking about ghost rings here.

As far as your "initiative" comment, you're acting pretty presumtive - I've been doing it all along, as have others - maybe if you would take the initiative to speak with a opthomologist or optometrist? But I think we all know by now that you won't.

If using a peep sight produces a greater depth of field that a ghost ring, then a ghost ring must produce a greater depth of field than normal vision. Perhaps this helps explain why my front sight and target are both in focus - despite opinions to the contrary. I know that the target would not be in focus if I was aiming with with open sights.

Yes, a ghost ring aperture will provide sharper focus/deeper depth of field than traditional open sights, just as a small aperture will do that much more so than a ghost ring. Or maybe, just maybe, you are mid-ranging, ie. focusing on an area somewhere between both objects, and each are therefore equally in focus, but niether exactly in focus; or are unable to discern the difference in focus; they can be very close, but two objects at different distances will not be "in focus", ie. exact focus.

jaycee - In the light conditions I have described, you might be able to tell the difference between a seal at 30 yards and one at 200, but you would be hard pressed to tell if the seal at 30 yards was at 30 or 100 yards. You cannot determine the difference between a seal at 100 yards and one at 300 yards in the light conditions I have described, without knowing the relative size of the seals in question - and there can be huge differences in size. Without the aid of technology (such as your very handy Barr and Stroud) or without the normal indexes we use to judge distance, we are lost.

Boomer, I'm not arguing that unaided rangefinding on ice, and especially with flat light it very difficult and approximate at best.

You might of hung around up here for a while, but unless you've been out on the sea ice in flat light you have no clue what I am talking about. The tundra is easier, although at times not much, because there are willows, grass and rocks to aid in our depth perception. On the sea ice in flat light, without colored glasses you cannot focus on the ground directly in front of you, you cannot see drifts, and you cannot see pressure ridges, unless there is enough light that they appear green. Ranging an animal or object of unknown size under these conditions is all but impossible. You know that your front sight is 30" from you eye, but if you don't think about that, it could be a dark post hundreds of yards away as far as you eye is concerned. If you observed a dark post hundreds of yards away and laid your front sight beside it, and both appeared to be the same size as you aimed through your ghost ring, each one would be in focus.

I've been on a lot of sea ice, from Puuvungnutuk (sp?) to Grise Fiord and points in between, and again I'm not arguing that it's difficult to range, much less see things (like drifts and pressure ridges) on ice in flat light. But if you can't tell the difference in focus of your front sight and a similar sized post hundreds of yards away, you are probably either mid-ranging or your vision isn't accute enough to tell the difference.

Now, if we return to normal light conditions, and the topography gives us a 3 dimensional view, should we encounter a similar arrangement with a target post alongside your front sight, the front sight and the post will still appear in focus.

See comment above....

Boomer, in all seriouseness, speak with either an optometrist or opthomologist. Since we've started this sparring match, I've spoken with 2 optomotrists and one opthomologist. Suffice to say, you wouldn't like their answers.

I don't know where you're located, but if you don't have a regular optometrist in town, there's probably one that runs a fly-in satellite office in town.

So how about it, willing to speak to one?

 

[Striker]

How ya doing now Jaycee?

 

[jaycee]

How ya doing now Jaycee?

 

[Striker]

rofl...

 

[Boomer]

Without putting words in his mouth, I understood Candown's post as saying he could not tell the difference between the focus of his front sight and the target, therefore I understood him to say that to his eye both appear to be in focus. If someone is going to tell me that a pin hole aperture produces a deeper depth of field than a quarter inch ghost ring I won't object.

As far as being presumptuous goes however, you have me beat. I would very much like to talk to the optometrist when he gets here, although I don't know when that might be as he only comes a couple of times a year. I would even be interested in hearing what your guys have said - although I am unsure how you would of posed the question to them. If I can learn something here then I am all for it, but you keep making statements which are contrary to my own observations and experience. Unless shown otherwise, I maintain that a front sight on a rifle is in the far focus range provided it is 30" from the eye, and the front sight and target are in simultaneous focus when viewed through an aperture rear sight.

I wonder what you would consider good shooting with a ghost ring and post?