Post by: Dave (Isle of Skye) on December 28, 2018, 07:44:21 am
So here is the puzzle that is starting to make my head hurt:
If you look at the boat in the foreground and its mirrored reflection, which is just a simple reflection of a small boat with an outboard motor on a flat calm loch, then how come you can also see the top of the boat in the reflection, when the water the reflection appears upon is never above the boat?
In other words, how can a reflection on the water below the boat, show part of the upper surface of the boat?
To explain how the shot was taken, as this might help even though it hasn't helped me, I was stood on a flat pontoon type of bridge about 5 feet above the water and the camera was mounted on a tripod at about 5 foot above the bridge, so the camera's viewpoint from the water is around 10 foot and the boat was about 50 or 60 foot out into the loch in front of me.
I am sure someone on here with a brain much larger than mine will be able to answer this conundrum, but for the life of me I can't see how this is possible.
Oh and if you are a scientist or something and you know the answer, can you use simple descriptions that I might be able to understand please :)
Thanks..
Dave
Post by: Aram Hăvărneanu on December 28, 2018, 10:42:40 am
Post by: Frans Waterlander on December 28, 2018, 11:53:53 am
Post by: Dave (Isle of Skye) on December 28, 2018, 12:21:21 pm
I am sorry, I don't understand the confusion. I see nothing wrong with the picture.
Hi Aram,
No I didn't say that there was anything wrong with the shot, I am asking how can something that I would have thought was hidden from the water, be reflected by the water?
Look at it this way: the top of the boat reflects the ambient light in all directions (just like any other part of the boat BTW); some of this light reflects in the direction of the photographer (you), clears the side of the boat, hits the water and then reflects off of it and voila, you and your camera see the top of the boat reflected in the water.
Thanks Frans for your answer, but I am sorry if I sound completely thick here, but are you saying that the reflected light from the top of the boat, is somehow bent around from the top of the boat onto the water and is then reflected into the camera?
I am not trying to obstinate here, I really just don't get how this trick of the light can work, because if the water is lying on a flat plane (as it obviously is) and the boat is sat on top of it, then how can anything above the flat plane of the water and that is therefore hidden from the water, then be reflected in it?
But after saying all this, perhaps it is just me and this conundrum has hit blank spot in my brain or something.
Thanks again guys ;)
Dave
Post by: Jeremy Roussak on December 28, 2018, 12:33:10 pm
The light which you see as the reflection (a virtual image) has travelled from the tip of the boat towards you and obliquely downwards, towards the water. It has struck the water and been reflected upwards to your eyes. The reason that you can see the tip in the reflection is that the path taken from the tip towards the water is sufficiently oblique (because you are a long way away) for it to clear the boat and hence to reach the water.
The reflection that you see doesn't lie directly below the boat; it comes from water behind the boat, nearer to you than the rear of the boat. So the point of the prow isn't "hidden" from it.
Does that help? I'd attach a diagram if I thought my drawing would do anything other than make things more obscure.
Jeremy
Post by: RSL on December 28, 2018, 02:19:01 pm
Post by: Slobodan Blagojevic on December 28, 2018, 02:37:29 pm
Interesting question, though.
I tried to replicate it. In the first image, done with a 28mm lens (eq.) close to the camera, the wick is not visible, as you would expect from something that is directly above the reflecting surface and obscured by the bottom of the candle.
However, when I extended the hand holding the mirror (to mimic the further-away vantage point) and used a 56mm lens (eq.), the wick is now visible, which in the first scenario appears physically impossible.
Post by: Ivophoto on December 28, 2018, 03:36:03 pm
Nice tries, but no cigar.
Interesting question, though.
I tried to replicate it. In the first image, done with a 28mm lens (eq.) close to the camera, the wick is not visible, as you would expect from something that is directly above the reflecting surface and obscured by the bottom of the candle.
However, when I extended the hand holding the mirror (to mimic the further-away vantage point) and used a 56mm lens (eq.), the wick is now visible, which in the first scenario appears physically impossible.
And the reflection of the wick is near to the mirror frame in the second image. In the first image the reflection of the cup is not over the middle of the mirror. This is what Jeremy is saying.
Hans Holbein used the perspective rule that create this confusion to his benefit in the painting ‘the ambassadors ‘
(https://uploads.tapatalk-cdn.com/20181228/21a139f5503c8fcaab2da9cae1ad7a2d.jpg)
Post by: Slobodan Blagojevic on December 28, 2018, 03:38:47 pm
And the reflection of the wick is near to the mirror frame in the second image. In the first image the reflection of the cup is not over the middle of the mirror. This is what Jeremy is saying...
Huh!?
Post by: Ivophoto on December 28, 2018, 03:40:20 pm
Huh!?
Hm, my crappy English doesn’t help.
Post by: Ivophoto on December 28, 2018, 03:42:58 pm
Huh!?
If you would keep the mirror flat and little under your eye level, the reflection will even touch the frame of the mirror close to you, not?
Post by: Ivophoto on December 28, 2018, 03:52:44 pm
Huh!?(https://uploads.tapatalk-cdn.com/20181228/62959b4929cd8f11ad824b2f1f2702e5.jpg)
(https://uploads.tapatalk-cdn.com/20181228/94bd54471b4fb1ff1b8f923e9ed54952.jpg)
(https://uploads.tapatalk-cdn.com/20181228/4bc82dd4a349d63c9ca8b19f6a587caf.jpg)
See?
Post by: Dave (Isle of Skye) on December 28, 2018, 04:47:03 pm
Nice tries, but no cigar.
Interesting question, though.
I tried to replicate it. In the first image, done with a 28mm lens (eq.) close to the camera, the wick is not visible, as you would expect from something that is directly above the reflecting surface and obscured by the bottom of the candle.
However, when I extended the hand holding the mirror (to mimic the further-away vantage point) and used a 56mm lens (eq.), the wick is now visible, which in the first scenario appears physically impossible.
Thanks for that Slobodan, but for your experiment to work correctly as compared to the original image of the boat, you would also need to see the top of the candle at the rear end of the candle - the bit of the candle furthest away from you when you took the shot. The wick in the second shot is just standing proud above the candle and is therefore reflected as expected at the distance you shot it. But even if you took a shot of the candle sat on the mirror from the other end of the room, would you then see the top of the candle in the reflection?
I think that the answer might be, that if the boat was a just a vertical picture of the boat stood vertically in the water, then obviously you would see the whole picture reflected in the water, so perhaps what is happening here, is that the reflection is somehow being created and then viewed on a vertical plane or a series of vertical planes - imagine a series of see-through mirrors all stacked in front of one another and that run all the way up to the sensor on my camera from the edge of the boat, which are again all set at a vertical plane to the horizontal water. Then the reflection you see here, is a sort of composite of all these slices of vertical reflections and as such, could then include the upper part of the boat - could that be it???
Jeremy, yes indeed please have a go at explaining this to me with a drawing if you would be so kind, as I would truly grateful to see what you draw.
I know this is just a bit of fun and the world will not stop spinning if I can't get my head around this, but it would be good to know how this has happened in a way that is easily understandable, so thanks everyone for your ideas and explanations and help, even though I am still struggling to get to grips with this ;)
Dave
Post by: Dave (Isle of Skye) on December 28, 2018, 04:53:37 pm
(https://uploads.tapatalk-cdn.com/20181228/62959b4929cd8f11ad824b2f1f2702e5.jpg)
(https://uploads.tapatalk-cdn.com/20181228/94bd54471b4fb1ff1b8f923e9ed54952.jpg)
(https://uploads.tapatalk-cdn.com/20181228/4bc82dd4a349d63c9ca8b19f6a587caf.jpg)
See?
Yes you have almost replicated this in the third shot, as we can see some of the upper parts of the object in the reflection of the mirror, so yes I agree the phenomenon can easily be replicated, but how is it possible to see something that is on the top of an object, being reflected in a flat plane surface that lies beneath it.
Thanks for all your help :)
Dave
Post by: Ivophoto on December 28, 2018, 04:57:04 pm
Yes you have almost replicated this in the third shot, as we can see some of the upper parts of the object in the reflection of the mirror, so yes I agree the phenomenon can easily be replicated, but how is it possible to see something that is on the top of an object, being reflected in a flat plane surface that lies beneath it.
Thanks for all your help :)
Dave
I think this is the graph Jeremy had in mind
Entry and exit angle is always the same. It is easy to imagine the further you are standing the flatter the reflected plane is.
(https://uploads.tapatalk-cdn.com/20181228/e55d171d1f5422d6baaa6ea5612c3f9d.jpg)
Post by: Telecaster on December 28, 2018, 05:24:13 pm
-Dave-
Post by: Dave (Isle of Skye) on December 28, 2018, 05:44:13 pm
I think this is the graph Jeremy had in mind
Entry and exit angle is always the same. It is easy to imagine the further you are standing the flatter the reflected plane is.
(https://uploads.tapatalk-cdn.com/20181228/e55d171d1f5422d6baaa6ea5612c3f9d.jpg)
But what about when the scene looks like this?
Thanks for your help by the way - Dave
Post by: Dave (Isle of Skye) on December 28, 2018, 05:46:39 pm
The light from the boat arrives at your eyes and your camera lens via a combination of smoother and rougher reflection surfaces due to motion in the water. The more diffuse light, coming from rougher portions of the lake's surface, gives you the seemingly impossible "view from above" in the reflected image. Atmospheric turbulence can also play a part in such phenomena. Light interacts strongly with "stuff." This is its job…it carries energy from thing to thing, and gets jostled around in the process.
-Dave-
Thanks for that Dave, don't know if it helps me understand fully, but certainly a worthy contribution to understanding the problem ;)
Dave
Post by: Ivophoto on December 28, 2018, 06:03:51 pm
But what about when the scene looks like this?
Thanks for your help by the way - Dave
Your boat doesn’t look like that.
Your boat looks a bit exaggerated like this
(https://uploads.tapatalk-cdn.com/20181228/5fc57793f4f2e297c89fe05e76273da0.jpg)
Post by: fdisilvestro on December 28, 2018, 06:30:18 pm
Turn the boat 180 degree and you will see the difference
Post by: OmerV on December 28, 2018, 08:13:10 pm
There is nothing strange in the reflection. The bow of the boat is much higher than the stern, that's why you see it in the reflection.
Turn the boat 180 degree and you will see the difference
This is correct. The reflection is creating an optical illusion that hides the difference in height between the stern and the bow.
Post by: Slobodan Blagojevic on December 28, 2018, 08:36:44 pm
... See?
What is there to see? Three identical reflections, the only difference being vantage point? Proving what exactly?
Post by: Slobodan Blagojevic on December 28, 2018, 08:42:29 pm
Post by: Slobodan Blagojevic on December 28, 2018, 08:44:56 pm
... smoother and rougher reflection surfaces due to motion in the water. The more diffuse light, coming from rougher portions of the lake's surface, gives you the seemingly impossible "view from above" in the reflected image. Atmospheric turbulence...
Replace water with a mirror and all that doesn't matter a bit.
Post by: LesPalenik on December 28, 2018, 09:42:45 pm
Post by: fdisilvestro on December 28, 2018, 10:02:11 pm
The real question here is this: how are we able to see inside the boat in the reflection? The inside that is blocked (from the reflective surface) by not only bottom of the boat, but sides too. I am not saying it is a miracle of any kind, just that someone needs to point out some laws of optics, and reflection diagrams, illustrating how reflections are made.
Because it is higher than the stern
Post by: OmerV on December 28, 2018, 10:36:23 pm
Because it is higher than the stern
Yep.
Post by: Ivophoto on December 29, 2018, 03:04:19 am
What is there to see? Three identical reflections, the only difference being vantage point? Proving what exactly?
See it together with the optical illusion in the painting.
Optically you see 3 identical reflections but the points of reflection are stretched over a longer surface of reflection.
The reflections are not identical. See the experiment with the paper boat.
It is first grade physics.
The law of reflection.
And telecaster is referring to the law of refraction. (Snell’s law)
Maybe, The latter can have little effect if there is pollution in the air, but is not what you see here.
Post by: Ivophoto on December 29, 2018, 03:06:32 am
Some reflections can be indeed puzzling.
You shouldn’t use LSD while using photoshop.
Post by: Ivophoto on December 29, 2018, 03:13:05 am
just that someone needs to point out some laws of optics, and reflection diagrams, illustrating how reflections are made.
?????
Do you read all posts, Slobodan?
Post by: Jeremy Roussak on December 29, 2018, 03:46:18 am
Ivo's diagram is more or less what I had in mind. I fail to see any relevance in the Holbein, which is an exercise in perspective.
Jeremy
Post by: Jeremy Roussak on December 29, 2018, 03:51:41 am
The light from the boat arrives at your eyes and your camera lens via a combination of smoother and rougher reflection surfaces due to motion in the water. The more diffuse light, coming from rougher portions of the lake's surface, gives you the seemingly impossible "view from above" in the reflected image. Atmospheric turbulence can also play a part in such phenomena. Light interacts strongly with "stuff." This is its job…it carries energy from thing to thing, and gets jostled around in the process.
Much of this is meaningless and that which isn't, save for the last sentence, is almost wholly wrong.
Unless warped by phenomena such as those giving rise to Fata Morgana, light travels in straight lines.
Jeremy
Post by: Ivophoto on December 29, 2018, 04:06:33 am
I fail to see any relevance in the Holbein, which is an exercise in perspective.
Jeremy
It is this perspective thing that confuses the viewer. You have the impression the reflected image is formed in front of the boat, but in reality it is formed over a long distance and the reason we see it in front of the boat is because this perspective thing.
The difference with the painting is that the skull is painted and not a latent image, so raising the point of view would not result in a stretched reflection of the boat but in another reflection, obeying the rule of reflection.
If the viewer would raise his point of view, he wouldn’t see the tip of the boat in the reflection because obscured by the stern.
Post by: Ivophoto on December 29, 2018, 04:10:25 am
Much of this is meaningless and that which isn't, save for the last sentence, is almost wholly wrong.
Unless warped by phenomena such as those giving rise to Fata Morgana, light travels in straight lines.
Jeremy
There is Snell’s law, light can get refracted in air, but in this case, it has nothing to do with the physical observation.
Post by: Dave (Isle of Skye) on December 29, 2018, 09:13:02 am
The real question here is this: how are we able to see inside the boat in the reflection? The inside that is blocked (from the reflective surface) by not only bottom of the boat, but sides too. I am not saying it is a miracle of any kind, just that someone needs to point out some laws of optics, and reflection diagrams, illustrating how reflections are made.
Absolutely Slobodan, you put it much more succinctly than I ever could and so the question remains, how the hell is this possible?
(https://forum.luminous-landscape.com/index.php?action=dlattach;topic=128266.0;attach=189583;image)
As I said earlier, the world will not stop spinning if this remains unexplained fully (to me at least), but even now with all the diagrams and suggested explanations (and thanks everyone for being willing to chip in), the answer to the question as Slobodan has now explained it more succinctly above, is still an unanswered optical conundrum I think.
The only answer I can come up with, is that reflections are to some extent more of a shallow depth and vertical, than they are deep in depth and lateral - in other words, we see and capture reflections with a bias towards the vertical and with a shallow DoF (perhaps something to do with our vertical viewpoint and independent of what f-stop we use - who knows?). So the boat in the reflection is not representative of a three dimensional object at all even though we assume it is, but is in fact a two dimensional representation of three dimensional object in the vertical plane? Therefore even though the loch surface is horizontal and below the boat at all times, the reflection it creates is vertical to our eyes and hence we can then see what we apparently shouldn't be able see, such as inside the boat?
Wow, have I gone and come up with the correct solution do you think?
I will be amazed if I have ;D
Dave
Post by: RSL on December 29, 2018, 09:28:06 am
Post by: Ivophoto on December 29, 2018, 09:37:57 am
Absolutely Slobodan, you put it much more succinctly than I ever could and so the question remains, how the hell is this possible?
(https://forum.luminous-landscape.com/index.php?action=dlattach;topic=128266.0;attach=189583;image)
As I said earlier, the world will not stop spinning if this remains unexplained fully (to me at least), but even now with all the diagrams and suggested explanations (and thanks everyone for being willing to chip in), the answer to the question as Slobodan has now explained it more succinctly above, is still an unanswered optical conundrum I think.
The only answer I can come up with, is that reflections are to some extent more of a shallow depth and vertical, than they are deep in depth and lateral - in other words, we see and capture reflections with a bias towards the vertical and with a shallow DoF (perhaps something to do with our vertical viewpoint and independent of what f-stop we use - who knows?). So the boat in the reflection is not three dimensional at all even though we assume it is, but is in fact a two dimensional representation of three dimensional object in the vertical plane? Therefore even though the loch surface is horizontal, the reflection it creates is vertical to our eyes and hence we can see what we apparently shouldn't be able see.
Wow, have I gone and come up with the correct solution do you think?
I will be amazed if I have ;D
Dave
Dave
Hahahahaha.
Come on. You got a sound and scientific complete answer.
Post by: Slobodan Blagojevic on December 29, 2018, 09:55:12 am
...You got a sound and scientific complete answer.
Which is?
Post by: Ivophoto on December 29, 2018, 09:56:18 am
Which is?
Again I have the impression loosing my time here on Lula.
Post by: Slobodan Blagojevic on December 29, 2018, 09:57:30 am
Again I have the impression loosing my time here on Lula.
You certainly are waisting mine.
Post by: Ivophoto on December 29, 2018, 10:18:05 am
You certainly are waisting mine.You are waisting your own time. You are looking blind in a fake problem.
Post by: Robert Roaldi on December 29, 2018, 10:33:45 am
But if you enjoyed that discussion then you'll like this: https://www.youtube.com/watch?v=jYmclzXff7o (https://www.youtube.com/watch?v=jYmclzXff7o).
Post by: rabanito on December 29, 2018, 10:36:24 am
I took this shot a few years ago and never thought too much about it after I'd finished working on it, but then the other day when I was reviewing some old files, I came across it once again and it started to make me think, how is that possible?
Misteries of Scotland.
While I was looking at the picture there appeared that creature from the right side.WITHOUT ANY REFLECTION!!!
Maybe my Knockando Single Malt 12 Years was bending the rays from the Sun? ;D ;D
Post by: Ivophoto on December 29, 2018, 10:48:53 am
The puzzle was explained back on p. 1 in reply No. 19. You are NOT seeing the inside of the boat. It's not an illusion.
But if you enjoyed that discussion then you'll like this: https://www.youtube.com/watch?v=jYmclzXff7o (https://www.youtube.com/watch?v=jYmclzXff7o).
Tx Robert.
Mid while I was wasting Slobodan time with this sketch, attempting to make it more clear.
(Let’s keep it friendly, Slobo. I like you, ....)
(https://uploads.tapatalk-cdn.com/20181229/73ccce805d85303e0ac4760b8db4fdd8.jpg)
Post by: Slobodan Blagojevic on December 29, 2018, 12:15:09 pm
... (Let’s keep it friendly...
How about a friendly explanation for the drawing? No diagram is worth anything without a legend. What are we looking at here? What is the solid red line and what is the dotted one? In which direction the lines go? Left to right or the opposite?
Are you saying that the reflection is formed by the light traveling from point A (intersection of the solid red line and the blue one) to the left, toward our eyes, and, upon hitting the water surface, is refracted backwards, this time left to right, until it forms the point B (intersection of the dotted red line and the blue one)?
In other words, the reflection is not formed in a vertical fashion, i.e., light traveling in a straight, vertical line between points A and B?
Post by: Ivophoto on December 29, 2018, 12:25:10 pm
How about a friendly explanation for the drawing? No diagram is worth anything without a legend. What are we looking at here? What is the solid red line and what is the dotted one? In which direction the lines go? Left to right or the opposite?Almost Exact, Slobodan.
Are you saying that the reflection is formed by the light traveling from point A (intersection of the solid red line and the blue one) to the left, toward our eyes, and, upon hitting the water surface, is refracted backwards, this time left to right, until it forms the point B (intersection of the dotted red line and the blue one)?
In other words, the reflection is not formed in a vertical fashion, i.e., light traveling in a straight, vertical line between points A and B?
The reflection is not following the path of your arrows, it doesn’t work like that.
Consider this: (On the left you have the viewers eye)
(https://uploads.tapatalk-cdn.com/20181229/23abfd2a19fa8a31850a5ed34ae32b02.jpg)
Point A is reflected in point C to the viewers eye. The viewer see it in the imaginary spot B. This is the law of reflection. Same as the imaginary image in a mirror is behind the mirror. It’s a bit quirky because here the mirror is horizontal. But same law applies.
https://courses.lumenlearning.com/physics/chapter/25-2-the-law-of-reflection/ (https://courses.lumenlearning.com/physics/chapter/25-2-the-law-of-reflection/)
Post by: Ivophoto on December 29, 2018, 12:31:36 pm
Other point of view, higher position, and you will not see the boat tip in the reflection.
(https://uploads.tapatalk-cdn.com/20181229/c7870c33ce61d2e4ad5111fc651c728b.jpg)
Post by: Frans Waterlander on December 29, 2018, 12:46:20 pm
Post by: Slobodan Blagojevic on December 29, 2018, 12:51:38 pm
It was explained in answer #2, but apparently it didn't sink in.
I am a photographer, hence prefer a visual explanation :)
Post by: Ivophoto on December 29, 2018, 12:54:45 pm
I am a photographer, hence prefer a visual explanation :)
Time for a cigar?
Post by: Jeremy Roussak on December 29, 2018, 01:08:45 pm
The diagram posted is very similar to the one I was about to post, which is attached. The light travels from the blob at the prow of the boat, is reflected off the water and reaches the eye.
You can see the inside of the boat. It is not an illusion. The light travels from it, isn't blocked by the rear of the boat, bounces off the water and reaches the eye, just as it does from the prow.
As I wrote in my first post on this topic, the reason Dave is confused (and his confusion seems to be afflicting others as well) is the misconception that the reflection you can see is real, that it somehow exists in the water below the boat. It isn't and it doesn't. It's a virtual image.
Look at the photo of a train on a bridge (I put a link in my last post in this thread). It makes the situation even clearer.
Jeremy
Post by: Jeremy Roussak on December 29, 2018, 01:14:00 pm
In other words, the reflection is not formed in a vertical fashion, i.e., light traveling in a straight, vertical line between points A and B?
Of course it's not! You have it!
Jeremy
Post by: Ivophoto on December 29, 2018, 01:30:00 pm
I am a photographer, hence prefer a visual explanation :)
Ha!!! I can help!! Imagine her ear is the tip of the boat.
(https://uploads.tapatalk-cdn.com/20181229/2a4912dc09b8eddf9dbbaf110079525e.jpg)
Post by: Slobodan Blagojevic on December 29, 2018, 01:38:20 pm
... The diagram posted is very similar to the one I was about to post, which is attached. The light travels from the blob at the prow of the boat, is reflected off the water and reaches the eye...
Sorry, Jeremy, still not buying it completely. Your diagram explains only what happens above water. How about refraction, which I think is what is necessary to understand what happens "under water," i.e., how/why the "virtual image" is formed and placed under the boat (and not at the point C, where in your diagram the light ray bounces off water into the eye). Ivo's diagram actually shows that.
Post by: Slobodan Blagojevic on December 29, 2018, 01:39:43 pm
Ha!!! I can help!! Imagine her ear is the tip of the boat.
Ear? What ear? ;)
Post by: Aram Hăvărneanu on December 29, 2018, 01:46:22 pm
Post by: Slobodan Blagojevic on December 29, 2018, 01:52:25 pm
There is no refraction involved, only reflection.
Can you elaborate? Are you saying that there is no refraction when the light ray hits the water/mirror surface?
Post by: Aram Hăvărneanu on December 29, 2018, 01:54:26 pm
Post by: Jeremy Roussak on December 29, 2018, 02:00:50 pm
Sorry, Jeremy, still not buying it completely. Your diagram explains only what happens above water. How about refraction, which I think is what is necessary to understand what happens "under water," i.e., how/why the "virtual image" is formed and placed under the boat (and not at the point C, where in your diagram the light ray bounces off water into the eye). Ivo's diagram actually shows that.
No, Slobodan. Nothing of any relevance is going on underneath the water.
Can you elaborate? Are you saying that there is no refraction when the light ray hits the water/mirror surface?
Only reflection is relevant: some of the light from the boat will not be reflected from the surface of the water but will continue into the water; that light will be refracted but unless you're diving you won't see it.
Jeremy
Post by: Ivophoto on December 29, 2018, 02:07:52 pm
Can you elaborate? Are you saying that there is no refraction when the light ray hits the water/mirror surface?
Forget refraction in this topic, it isn’t relevant.
It is in this image
(https://uploads.tapatalk-cdn.com/20181229/7a41cc9256b149a90d9b54dbde9cb3cb.jpg)
Post by: Slobodan Blagojevic on December 29, 2018, 02:08:55 pm
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.
Post by: Slobodan Blagojevic on December 29, 2018, 02:11:25 pm
No, Slobodan. Nothing of any relevance is going on underneath the water...
Ok, let's forget water and concentrate on mirrors.
Post by: Ivophoto on December 29, 2018, 02:15:59 pm
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.
Post by: Ivophoto on December 29, 2018, 02:18:16 pm
Ok, let's forget water and concentrate on mirrors.
Ok
=>
(https://uploads.tapatalk-cdn.com/20181229/ae1039b2ffa5c26fa9e13c1aa6884d3a.jpg)
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.
Post by: Aram Hăvărneanu on December 29, 2018, 02:21:23 pm
Post by: Slobodan Blagojevic on December 29, 2018, 02:21:29 pm
Post by: Ivophoto on December 29, 2018, 02:31:58 pm
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.
(https://uploads.tapatalk-cdn.com/20181229/1ff84fee4d1212dc1422b2cb57ead512.jpg)
Post by: OmerV on December 29, 2018, 04:00:21 pm
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.
Post by: Ivophoto on December 29, 2018, 04:42:02 pm
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:
(https://uploads.tapatalk-cdn.com/20181229/7aaaa85496948fa1de43aa81a7e306b6.jpg)
Wide angle
(https://uploads.tapatalk-cdn.com/20181229/197b9cb5a3f59d32b8e4c99a0be692a1.jpg)
Post by: mouse on December 29, 2018, 04:56:51 pm
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.
Post by: Telecaster on December 29, 2018, 06:36:56 pm
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. ;D I was just wingin' it with half-remembered quantum electrodynamics, not really appropriate for describing wave behavior.
-Dave-
Post by: degrub on December 29, 2018, 07:43:19 pm
Post by: OmerV on December 29, 2018, 10:41:30 pm
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.