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Hi - new to the forum with a question |
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hasbo
Optics GrassHopper Joined: July/07/2021 Location: Nottingham Status: Offline Points: 9 |
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Posted: July/07/2021 at 15:38 |
I measure the eye relief by shining a light through the objective and seeing how far away from a surface the smallest exit pupil is :-
[The peripheral ring of light is stray light .] Too close to the ocular and I can see an image of the reticle :- Too far out and I can see an image but it is INVERTED (and reversed) :- The only problem is - no matter how I try or what I do, I can't get this effect when I look through the scope.
[it happens for sunlight as well as torchlight - the same effect whether 1st or 2nd focal plane. ] {sorry about the picture quality - it is usually much better - but can anyone explain this ??} |
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Scrumbag
Optics Master Extraordinaire Joined: October/22/2013 Location: London, UK Status: Offline Points: 4205 |
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So what's your issue? Is the image upside down when you look through the scope? Might be worth just fitting the scope so it works with your eye... Welcome on board from London!
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Was sure I had a point when I started this post...
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hasbo
Optics GrassHopper Joined: July/07/2021 Location: Nottingham Status: Offline Points: 9 |
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I know full well that the scope works for my eye in practice (it was previously fitted to a rifle).
[This one was chosen as it had a vertically asymmetrical reticle so the inversion could be see.] My problem is, it is something I don't understand and I would like to. I posted the same thing on another forum (NOT Optics specific) and had this response :- "I guess that makes sense - 'focuses' at the point the exit pupil appears smallest and then the 'rays' continue and cross over inverting the image...." To which I replied :- "Yes - BUT - I can see it as a projected image (clearly inverted) but with my eye in the same position as the screen it isn't inverted. Try it with any scope you like, but it has to be a vertically asymmetric reticle or you can't tell the difference. "To which he replied :- "That's weird" And I said :- "Ain't it just. "
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hasbo
Optics GrassHopper Joined: July/07/2021 Location: Nottingham Status: Offline Points: 9 |
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Problem solved, I now know the reason and my curiosity is satisfied.
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Urimaginaryfrnd
MODERATOR Resident Redneck Joined: June/20/2005 Location: Iowa Status: Offline Points: 14964 |
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WHY...........
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"Always do the right thing, just because it is the right thing to do". Bobby Paul Doherty Texas Ranger |
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hasbo
Optics GrassHopper Joined: July/07/2021 Location: Nottingham Status: Offline Points: 9 |
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One is the "real" image of the reticle - the other is the "virtual" image.
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Son of Ed
Chuck Norris Joined: June/18/2011 Location: TEXAS Status: Offline Points: 122166 |
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Actually, I'd rather hear about Nottingham....
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Visit the Ed Show
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hasbo
Optics GrassHopper Joined: July/07/2021 Location: Nottingham Status: Offline Points: 9 |
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My apologies - I misinterpreted the nature of this forum, the name is a little misleading.
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Urimaginaryfrnd
MODERATOR Resident Redneck Joined: June/20/2005 Location: Iowa Status: Offline Points: 14964 |
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Tell us about Nottingham. The forum offers many different things but for me I am more into practical applications of optics particularly tactical optics. Koshkin is well educated in Optical Physics so perhaps he would have more insight into technical questions. And we would love to hear how things are in Nottingham.
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"Always do the right thing, just because it is the right thing to do". Bobby Paul Doherty Texas Ranger |
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Kickboxer
MODERATOR Moderator Joined: February/13/2008 Status: Offline Points: 23679 |
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Many addressements of this question on Youtube... didn't see the need to go over it again.
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Opinion,untempered by fact,is ignorance.
There are some who do not fear death... for they are more afraid of not really living |
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