why do lenses make everything look upside down?
832292
Not all lenses do that, just convex lenses.  Know anyone that wears glasses?\nYou'll lear how lenses and prisms work when you take physics 2.\n\n-jose-
293067
You also may want to ask the optometrist - I have astigmatism and when I went in for new contacts 6 months after my last eye exam, I found out my eye had changed shape quite a bit, changing my prescription for the toric lense (my weights wouldn't hold in the right place).  The blurriness has to be the weight swinging wrongly.  \n\nYou know, it could also be that the company screwed up on your order - maybe give them a call.
8548
Close.  I would say it's because the photons from the object hit a smaller area of the cornea.  If you think of the surface of the cornea as a screen onto which the world in front of the viewer is projected through a lens, as an object is moved away the angle between its top and bottom gets smaller and so the relative size of the object in that projection gets smaller.
1065132
Its hardware problem\nIf in warranty get it replaced but if not u'll have to get it repaired. Generally this happens due to Lens problem.
303018
Did you buy glasses? It sounds about like the price and description of two lenses. If your didn't buy glasses, you'd better ask them, maybe they made a mistake.
108047
reality (the first answerer) is mostly correct, but it's more of a phychological effect than an optical illusion. When you look in the mirror and raise your right hand, it looks like "the guy in the mirror" is raising his left hand. Because of this, you perceive the mirror to be flipping left and right. But all the light is just being reflected directly back. If you hold writing up to the mirror, it looks backwards left to right. If you hold it vertically, it looks backwards top to bottom. There is no left-right top-bottom asymmetry. Think about it for awhile and you will realize that a mirror doesn't "flip" anything, it's all in your mind.
701665
Because they're crooked!
111058
reflection can produce a differnt image.. but translation is moving the image up down right or left
160744
I suspect that the focal length would change sign.  That is, a convex lens would now act like a concave lens and vise versa.
86922
They are both done optically, it is just how it is processed that is different.  By that I mean one is on film and the other is stored digitally, however it is still the movement of the lens that increases or decreases power of the image for the picture.
409083
It has nothing to do with the two halves of the lens anyway. The way I can explain it is spherical abberation, i.e due to the difference in the foci for the edge of the lens and the middle of the lens. But that would form a blurred image and not two images.
943525
You need to adjust your contrast.
478046
Only on the concave(front) curve of the spoon will give an upside down reflection.  The distorted surface of the spoon reflects light from yourself at angles which result in an inverse image in the spoon.  This is actually called refraction.
1079643
actually it's called "astigmatism."\n\ntry - http://www.allaboutvision.com/conditions/astigmatism.htm
227084
Your photos are over-exposed. Just like the reason why you shouldn't look at the sun with the naked eye, pointing the sun at any electronic optical equipment won't work properly. You should have used a strong filter to stop the glare.
52768
B.  A convex mirror will make light diverge, and no mirror will *alwats* give a inverted image, because it depends whether you're closer than the focal point for a concave lens.\n\nThink about those little round mirrors on buses and huge trucks, and how small the image is.  Those mirrors are convex.
945701
playing around with mirrors....and light.....and lenses