Here is a Photographic Puzzle for you all...

[Slobodan Blagojevic]

There is refraction happening when light hits the water, but it's irrelevant in this particular case as you can't see it (it's only relevant for the fish in the water). You only see the reflection, like with the mirror (in the case of the mirror there is only reflection, no refraction).

Fair enough.

I am trying to understand how the "virtual image" is seen as under the boat, and not at the point of reflection (C). Is our mind creating the placement? In other words, I am interested in how's the dotted line in Ivo's diagram formed.

[Slobodan Blagojevic]

No, Slobodan. Nothing of any relevance is going on underneath the water...

Ok, let's forget water and concentrate on mirrors. 

[Ivophoto]

Fair enough.

I am trying to understand how the "virtual image" is seen as under the boat, and not at the point of reflection (C). Is our mind creating the placement? In other words, I am interested in how's the dotted line in Ivo's diagram formed.

The clue is in the Holbein painting and in the exercise with the nail polish bottle on my wife’s mirror.

It is a bit skewed comparison because the skull in Holbein’s painting is real and the reflection is virtual, but I find it a good hint how we see the assembly of reflections in scale and under the boat from that slant angle over the mirroring water surface.

[Ivophoto]

Ok, let's forget water and concentrate on mirrors.

Ok
=>



Now, draw the mirror under here feet, draw the viewers eye on the right and draw the lines following the law of reflection and,... voila.

[Aram Hăvărneanu]

No, the virtual image is not formed only in our minds. That's why we can photograph it. It'a a real thing, the "virtual" nomenclature only means the rays of light merely appear to converge from some point in space, but don't actually come from that point (they come from above the water, while they appear to come from below the water). This is opposed to a "real image", where the rays of light come from where they converge. The only difference between real and virtual images is that you can project (on a screen, film, sensor, what have you) a real image, but you can't directly project a virtual image. From "the outside" real and virtual images appear and behave the same.

[Slobodan Blagojevic]

I know, Ivo. My question remains: what creates the dotted (blue) lines? Our mind's imagination or some law of optics?

[Ivophoto]

I know, Ivo. My question remains: what creates the dotted (blue) lines? Our mind's imagination or some law of optics?

The optic law that I linked you to in a previous  post.

The law of reflection.

[OmerV]

Fair enough.

I am trying to understand how the "virtual image" is seen as under the boat, and not at the point of reflection (C). Is our mind creating the placement? In other words, I am interested in how's the dotted line in Ivo's diagram formed.

It's an optical illusion or distortion caused by the distance of the viewer, akin to using a telephoto. Were you to walk on the water (you can, right?) and use a wide angle lens to make the same photo, the reflection would stretch towards you and not appear to be under the boat. The hight of the bow allows the light bouncing off the top of the boat to partly go over the side of the boat and be reflected on the water. The rest of the boat is easily reflected, and again, compressed by distance making it appear to be under the boat.

[Ivophoto]

It's an optical illusion or distortion caused by the distance of the viewer, akin to using a telephoto. Were you to walk on the water (you can, right?) and use a wide angle lens to make the same photo, the reflection would stretch towards you and not appear to be under the boat. The hight of the bow allows the light bouncing off the top of the boat to partly go over the side of the boat and be reflected on the water. The rest of the boat is easily reflected, and again, compressed by distance making it appear to be under the boat.

The above is simply not correct. And the reason it is not correct is because it is not an image on the reflecting plane (as the Holbein skull is on the canvas) but a virtual image obeying the law of reflection.

Look:

Tele:


Wide angle

[mouse]

Can you elaborate? Are you saying that there is no refraction when the light ray hits the water/mirror surface?

The reflected light would indeed be refracted; if the observer were under water.

[Telecaster]

Thanks for that Dave, don't know if it helps me understand fully, but certainly a worthy contribution to understanding the problem 

There are far more useful responses in this thread than mine.     I was just wingin' it with half-remembered quantum electrodynamics, not really appropriate for describing wave behavior.

-Dave-

[degrub]

surfs up ! 

[OmerV]

The above is simply not correct. And the reason it is not correct is because it is not an image on the reflecting plane (as the Holbein skull is on the canvas) but a virtual image obeying the law of reflection.



You are correct, Ivo. I made the mistake of making the reflection a separate element from the boat. Yet your illustration does suggests that a tele perspective(distance) is, for some, creating a confusing doppelgänger illusion.