jmkelly
rangefinder user
Rolo - we like to see images made by a 50mm on 135 because the perspective looks natural to us. No matter the size of the image or the perspective it was generated from (fish-eye to tele) we still perceive that image from the center of our eye - indeed like a torch in the dark.
Bobfrance
Over Exposed
Great thread (thanks Stewart!).
I'd really like to understand the mechanics of why 50mm (or any other focal length) seems natural to us.
I'd really like to understand the mechanics of why 50mm (or any other focal length) seems natural to us.
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bensyverson
Well-known
50mm doesn't seem "natural" to me... Speaking for myself, 28mm or 35mm feels more natural.
antiquark
Derek Ross
I once read an explanation which was based on the idea that we're three-dimensional creatures, so we have the ability to perceive a two-dimensional surface "all at once."
So if you want to "absorb" something pseudo-instantly, just by looking at it, it will have to be a 2D object (such as a photograph).
A 3D thing, you can't see "all at once", you have to walk around it, or turn it around, etc.
Chris101
summicronia
Well our eyes project on the inside of a sphere. So did old-time televisions, but we watched them from the outside. Planetaria are usually projected on a sphere too. And I remember at disneyland many decades ago a cylindrical room where all the walls were projection screens - the effect was dizzying.
LKeithR
Improving daily--I think.
Man, I just came here to look at pictures and now my head is spinning...
Richard G
Veteran
We don't necessarily see instantly. A picture is built, preferentially taking in what is most useful. Sitting in my car, looking straight ahead, I can see the pendular movement of the fluffy dice hanging from the rear view mirror of the car next to me, 90 degree angle. I am wearing multifocals with a very narrow central band of clear focus which I am now sufficiently used to that I don't notice the restriction. There is a brain condition that sees normal visual acuity, normal visual field and normal eye movements but an inability to reconstruct an image. A laptop may be perceived as something with the letter G on it but the whole object cannot be taken in. For most of what we do that's fine work we are looking straight ahead. Some gimble eyed reptiles operate differently. The Lascaux caves provided a flat surface. Raffaello's Papal apartment frescoes almost approached the 3D, taking up whole walls. Try sitting there, or the front row with a 70mm movie projected and the ultra wide capacity of the human is sorely tested.
http://imgs.xkcd.com/comics/trapped.png
http://imgs.xkcd.com/comics/trapped.png
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Sparrow
Veteran
I believe the concept of a natural FOV equivalent for the eye to be pretty bogus. The eye is like a small torch scanning a dark room. Anything outside that tiny point that is largely a virtual construct generated by the brain. Perhaps this is where the planar representation comes from.
How this equates to 35mm is intriguing but beyond me.
I have been drinking wine tho'...
I think that's a great analogy for what actually happens, well what I perceive happening ...
I know, from one of them book things, that the image formed on the retina is "projected" at the back of the brain, we form that data into a planar projection ... a cow, however, probably uses a different projection simply because of the sighting of it's eyes
Roger Hicks
Veteran
Dear Stewart,
Possibly because a small child is not usually at such risk from its environment, as it is protected by its parents?
As I said before, it's probably a very good compromise for covering a large area (more or less) simultaneously, and also, it's probably easier to scan a flat area (or one perceived/constructed as flat) than to scan (say) a fisheye area, where the relative shapes asnd sizes of things change with every eye movement.
I assume you meant 'BC' about the Greek theatre, as I vaguely recall references to it in Roman theatre.
Cheers,
R.
Sparrow
Veteran
I would have thought 3,000 years ago the first 3 or 4 years of a child's life would have been statistically the most dangerous.
I did consider projectile-weapons being the driver, like a spatial relationship thing, but clearly those French cave-painters could hit a wooly-mammoth with a pointed stick as well as the next man, and did it for many millennia, and almost to the end of the gothic people were OK with princes depicted three times the size of their subjects and throwing stones at each other ...
I have an idea the Greek theatre reference is is from Herodotus, but don't quote me as it's years since I read it. There was definitely a style of Roman wall painting illusionism by the start of the Christian era, but it was just one of a number, four iirc
Roger Hicks
Veteran
Dear Stewart,
Not, I suggest, when you consider the risks of murder and being eaten by wild animals, precisely because of the ring of protection created by adults. It's marauders and wild animals where the planar projection is so handy, and is therefore adopted.
Further thought: representational conventions can arise for all kinds of odd reasons. Conthider the Thpanish lithp and the French habit of not pronounc(ing) the en(ds) of their wor(ds).
Also: Switching between planar (hunting) and one-pointedness (chucking the spear) is what we all do, all the time.. If you only paint what you think is important, instead of all of what's there, other projections make more sense.
As soon as realism (as distinct from iconography) becomes important, planar projections win. Why did artists adopt realism? Because they could...
Cheers,
R.
bobbyrab
Well-known
Forgive my ignorance, just trying to clarify in my mind what's being discussed. Is the proposition here, that there is an alternative way to render a 3d image into 2 dimensions than the current convention in photography and painting? If so could I be directed to any examples, particularly in photography, I would imagine examples in painting would be easier and include works such as Picasso, but please enlighten me. With regards painting, I was once told buy my history of art tutor, that early paintings that moved away from straight 2d paintings, and recreated 3d by perspective and shading, were completely perplexing to early audiences, they had to learn as we have to read the representative language, but once learned it's impossible to unlearn, so I assume any alternate perspective would be baffling. With regards normal lenses, I always think a 50mm shows pretty much the area of vision your able to pull reasonable and accurate information from, but a 35 to my mind is a more natural view as it includes your very informative peripheral vision, wider than 35 and the information becomes too vague, so the view of a 28 is more than I can see, but that of course will be subjective. However getting back to the original question, are there other designes of lens that would render perspective differently.
Sparrow
Veteran
Roger
I suppose it would depend on the variety of threat, it does seem self evident that binocular vision and therefor, presumably, the planar image is the domain of the predator in nature rather than the prey.
I started wondering about this after a trip to the Media Museum last week, I was in an antique shop in the morning looking at a huge number of 19c Japanese prints, followed by the super-reality of the IMax in the afternoon ... it started the thought experiment "what do I actually see"
I'm pretty sure representational convention is a big part of the depiction of reality but what part does it play in its' perception.
Sparrow
Veteran
I suppose the Albers projection would be the equivalent of a fish-eye lens, where area remains constant but angular relationships change.
Our eyes have almost a 180 degree FOV but only the centre 5 to 10 degrees is resolved and coloured properly
Sparrow
Veteran
I think our optic-nerves end at the visual cortex, so one could say it's rather like a planetarium with our self sat in the middle ...
Roger Hicks
Veteran
Dear Stewart,
Of course, there's nobody on RFF that self-centred...
As for binocular vision being the preserve of the hunter, not the hunted, well, 3-4 is the age children start to take more command of their surroundings -- in preparation for hunting?
Cheers,
R.
ZeissFan
Veteran
This is why I'm not an academic. I don't understand anything that's being said here. And I'm being serious.
MickH
Well-known
I'm a bit lost with some of the heavy theory too, but I remember learning at school that although we have a wide field of view, all we can really concentrate on in any given instant is an area about the size of a 50p piece held at arms length, which is why we scan photographs, paintings and, of course read about one word at a time. I wonder if chinese writing is more efficient to read? Do the characters carry more information per eye-full than your European writing?
@ Bobbyrab.. here's an example of how different focal lengths can affect the way an image looks, it's more graphic in motion, but comparing photographs taken with different focal lengths and from different distances will show something similar...
http://www.youtube.com/watch?v=iv41W6iyyGs
@ Bobbyrab.. here's an example of how different focal lengths can affect the way an image looks, it's more graphic in motion, but comparing photographs taken with different focal lengths and from different distances will show something similar...
http://www.youtube.com/watch?v=iv41W6iyyGs
ferider
Veteran
Just to illustrate my point, Stewart:
Wonder how many axonometric projections are out there, compared to, say, published photos ...
Roland.
Wonder how many axonometric projections are out there, compared to, say, published photos ...
Roland.
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Sparrow
Veteran
Just to illustrate my point, Stewart:
Wonder how many axonometric projections are out there, compared to, say, published photos ...
Roland.
Well yes, but there are two things wrong with that, firstly to be a true planar projection the verticals should diverge, and those have been distorted to retain the vertical dimensions, so some distortion has been introduced elsewhere.
... and secondly, that M2 has a M4 base-plate, which is also wrong