Author Topic: Perception  (Read 32243 times)

Offline JayUtah

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Re: Perception
« Reply #15 on: November 21, 2012, 12:46:57 PM »
When I got seriously into photography in the early '70s I slowly became astonished over how lousy my perceptions had been of what I saw -- how many things I had "seen" but never really noticed and appreciated for what they really were.

This is true for any synthetic lighting experience, including stage lighting.  Expertise in lighting and composition for film or stage comes only after one has acquired a conscious awareness of one's perception of detail, form, contour, shadow, juxtaposition, luminosity, hue, and saturation.  You can find any number of illustrations of these perceptual filters in the form of optical illusions, especially the ones that ask you to judge relative brightness.

Especially in cinematography, one's natural sense of hue and lightness must be explicitly overridden to accommodate lighting and film "temperatures."  Having worked in theater for years, and having been a photographer for almost as many years, I was still also astonished when I began working in Hollywood.  For example, the rich reds of TNG/Voyager Starfleet uniforms (as photographed) are actually almost a comical fuscia in natural light.  The "black" parts are actually a surprisingly light gray.  These costumes were designed by experts who knew not to trust their perception under the work lights, but who understood how the studio lights would "shift" their creation toward the actual intent.

Similarly I have watched novice scenic artists paint masterpieces as seen under the shop lights, but which turn to gray mush on stage.  They failed to consult the lighting designer.  If they want any sort of chromatic perception under subdued and possibly limited wavelengths, they need to make their piece look like someone threw up Skittles on it.
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Offline ChrLz

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Re: Perception
« Reply #16 on: November 22, 2012, 07:42:03 AM »
Another thing that wakes us up regarding our perceptions is to see an extremely wide-angle photo of a recognisable scene, such as a shot of a long brick wall with the lens axis at right-angles to its centre.  Often viewers will exclaim that the wall is distorted, but, except for the usual minor distortions of most lenses, that might not be the case.  The main problem is that our brains are too good at reinterpreting things we see and making them acceptable to us.  We need to study that wall from the same perspective as the camera, turning our head up, down and to both sides, and noting how the lines of of the bricks recede to a vanishing-point in all areas except those very close to the lens axis.

Thank heavens there are others that GET this!!!!  I've had some extremely frustrating  discussions with folks who maintain that straight lines are always straight, and that effects as wide-ranging as the Moon-tilt 'illusion' thru to fish-eye curvature of the view from a very short focal length lens are all nothing but illusions and lens effects..

I'm thinkin' about writing a web article about this topic, as I haven't found many decent references..

Quote
It can be quite startling to stand at the centre of an end wall in any large, rectangular room in a house and hold up two straightedges so that they match the joins between the side walls and ceiling or floor.  Betcha your brain has been deceiving you all along over how sharply they converge to a vanishing-point.
That's one of the ways I try to explain it, but it seems it just doesn't get through - even to some folks who should really know better.

Offline Sus_pilot

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Perception
« Reply #17 on: November 22, 2012, 10:53:17 AM »
Part of the issue is that artists "correct" what they "see" to match their perceptions, rectifying the primary object to be "square". Thus, we've been trained that this is how the world should be.  Hence, view cameras where the focal plane is set parallel to the object to be photographed, squaring it up, because that's the most pleasing.

The difficulty is that there is no single objective reality.  It depends on what you're trying to accomplish. An object that fills a frame with a long lens looks remarkably different than an image of the same thing taken with a long lens (Hitchcock and his cinematographer used this to remarkable effect in Vertigo by trucking the camera and changing the focal length of a zoom lens at the same time, keeping Jimmy Stewart the same size in the frame).

As I said, it depends what you're trying to accomplish.  Just remember, never take a tight close-up of someone with a short lens if you want to stay friends...

Offline AtomicDog

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Re: Perception
« Reply #18 on: November 22, 2012, 12:49:41 PM »

Having worked in theater for years, and having been a photographer for almost as many years, I was still also astonished when I began working in Hollywood. For example, the rich reds of TNG/Voyager Starfleet uniforms (as photographed) are actually almost a comical fuscia in natural light.  The "black" parts are actually a surprisingly light gray.  These costumes were designed by experts who knew not to trust their perception under the work lights, but who understood how the studio lights would "shift" their creation toward the actual intent.



You worked on TNG and Voyager? Tell us more!
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Offline gillianren

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Re: Perception
« Reply #19 on: November 22, 2012, 02:07:45 PM »
Jay, you have interested Graham again!
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Offline raven

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Re: Perception
« Reply #20 on: November 22, 2012, 04:40:37 PM »
*raises hand* I would also be interested to hear of this.

Offline JayUtah

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Re: Perception
« Reply #21 on: November 23, 2012, 12:04:59 AM »
You worked on TNG and Voyager? Tell us more!

I wish!  I worked at Paramount (and Warner Bros.) on and off on other smaller projects for several years, commuting from Utah as needed.  But I managed to spend a bit of time visiting Star Trek sets when they were open, and occasionally with the members of the cast and crew during their breaks.  That's how I know what the costumes and other items look like in natural light.  Previously I had met Patrick Stewart while I was working on the stage crew at Kingsbury Hall (Univ. of Utah) when Stewart was touring his one-man Christmas Carol.  I wish I could say he remembered me when I ran into him again as Capt. Picard, but he did not.

I had more occasion to talk to the Voyager cast and crew, and to meet one of my acting muses Ethan Phillips.  It was a bit surreal to share coffee with him while he was in Stanford sweats but full Neelix makeup.  By that time most of the Star Trek stages were a little more tightly controlled, but it's amazing how far you can go with a "crew" badge.  It also helps if you befriend minor cast members and the crew who will vouch for you.  Normally in a major studio, the convention is that if a stage's "elephant door" is open, visitors can enter the stage.  However, for Star Trek stages you still needed production-specific credentials to be on the stage, mostly because props and things had a habit of going missing, to be sold to collectors.  I was surprised at how many extras and bit players were Star Trek fans, and had turned down other, better-paying work to get to be in a Star Trek episode.
"Facts are stubborn things." --John Adams

Offline JayUtah

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Re: Perception
« Reply #22 on: November 23, 2012, 12:15:45 AM »
(Hitchcock and his cinematographer used this to remarkable effect in Vertigo by trucking the camera and changing the focal length of a zoom lens at the same time...

Dollying.  Trucking is moving left or right, relative to the optical axis.  Dollying is moving forward or backward along the optical axis.  The cinematography term for this is simply the "dolly zoom," although it was referred to briefly as the "Spielberg zoom" when I was studying cinematography because the prevalent example of it had become Jaws.  It's even a pre-programmed macro in some motion-control systems.

But yes, the proper distance from the subject versus the focal length is something you study also in still photography to properly compose a portrait and to properly manage the depth of field and focus.  And you must be consciously aware of how the camera renders the impression of relative distance versus how your eyes perceive it.  That it is typically unconscious in most people is how the dolly zoom achieves its unsettling effect.
"Facts are stubborn things." --John Adams

Offline Kiwi

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Re: Perception
« Reply #23 on: November 23, 2012, 04:39:34 AM »
Hitchcock and his cinematographer used this to remarkable effect in Vertigo by trucking the camera and changing the focal length of a zoom lens at the same time, keeping Jimmy Stewart the same size in the frame

Thanks for that.  I saw Vertigo about 1959-60 when I wasn't yet a teenager, so wouldn't have taken much notice of that effect, but when watching the DVD of Jaws a few years ago I certainly noticed, because that was the earliest example of it (1975) that I could recall, and I wondered who originated it.

Does anyone know exactly where that scene is in Jaws?  From memory it's a shot of Roy Scheider sitting on the beach and he realises the shark is starting to "bother" people close to shore, round about the time that a dog disappears.

The effect is currently in an advertisement on New Zealand TV where a young couple is house-hunting.  It's a view of them standing back-on to the camera and facing a house they like.  The lens might have a bigger zoom range than the one in Jaws.

The DVD of Vertigo has been selling here for around $10 recently, so I must grab it.  Maltin says it's a great film, and it lingered in my memory for a few years.

Just remember, never take a tight close-up of someone with a short lens if you want to stay friends...

Oh, I dunno about that.  We have a lot of Polynesians in New Zealand and some have fairly flat, wide faces with even flatter and wider noses, so careful use of a shorter lens, closer in than usual, often gained me happy customers.  Conversely, someone with a very long nose can be made to look better with an extra-long lens.  The whole art of being a successful portrait photographer is, in some cases, re-interpreting reality.  Painters have probably done that for centuries.

The difficulty is that there is no single objective reality.

A favourite escape clause of mine is, "Everything is relative and every situation is unique.  Everything depends on something else."  It got me out of all sorts of trouble.

A classic case is the derisive expression, "Aw, c'mon man, it's just common sense." For something to be common sense, you have to be in possession of the appropriate information.
« Last Edit: November 23, 2012, 04:44:17 AM by Kiwi »
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Offline Kiwi

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Re: Perception
« Reply #24 on: November 23, 2012, 05:10:34 AM »
...the proper distance from the subject versus the focal length is something you study also in still photography to properly compose a portrait and to properly manage the depth of field and focus.  And you must be consciously aware of how the camera renders the impression of relative distance versus how your eyes perceive it.

Getting a good full-face portrait on a large-format studio film camera of a long-nosed dog can be quite difficult.  You need to know that you have sufficient depth of field to cover the distance between at least the tip of its nose and its eyes, but preferably its ears too, and often in a studio you won't be able to see exactly how much depth of field you have at a small aperture.  You also need to know that about two-thirds of the depth of field will be sharp behind the point of focus, and one-third in front, and focussing on the appropriate point can be difficult if the dog isn't too happy about sitting or standing still.

It's worth studying similar photos to see if the photographer stuffed up.  Some don't even try it.  It might be easier when using digital cameras with their smaller image size, assuming that the manufacturers actually publish such esoterica as depth of field information.
« Last Edit: November 23, 2012, 05:30:27 AM by Kiwi »
Don't criticize what you can't understand. — Bob Dylan, “The Times They Are A-Changin'” (1963)
Some people think they are thinking when they are really rearranging their prejudices and superstitions. — Edward R. Murrow (1908–65)

Offline Kiwi

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Re: Perception
« Reply #25 on: November 23, 2012, 06:51:13 AM »
Thank heavens there are others that GET this!!!!

There certainly aren't many HBs who get it, just as there aren't many HBs who think to pause and spend a few seconds laying straightedges along the “parallel” shadows that Bennett and Percy show them on page 22 of “Dark Moon” and in their video, or the shadows that Sibrel shows them in his video, “A Funny Thing Happened on the Way to the Moon.”  I suppose that the few who do have the brains to check don't claim the moonlandings are hoaxed because they already  know that they've been taken in by people who deal in terminological inexactitudes.

...effects as wide-ranging as the Moon-tilt 'illusion'...

Haven't heard of that one, but I do know about the "gigantic" full moon as it rises behind a hill or distant trees.

It can be fun at any gathering where there is no moon visible, to hold up both hands with thumbs touching, fingers splayed, little fingertips and thumbtips in a straight line, and arms straight, and ask everyone to say how much of those two handspans they think it takes to cover the full moon, or even the rising full moon.  It might also pay to say that those who know the exact answer should say nothing.

I've even had people say the whole lot -- 40 degrees roughly!  Very few people will say that they could cover two moons with one fingertip and some may not believe the correct answer.  It's an excellent example of how people perceive things -- even something they might have seen over and over for many years.

Another interesting way to mess with perceptions and maybe see the fur fly is, at a gathering of parents, ask the fathers if they would be perfectly happy for their teenage daughters to meet guys who are exactly the same as they were when they were teenagers.

Just be aware that it might pay to stand at least 1-1/2 arms-lengths from anyone you ask, and that doing so could cause a divorce!

I can honestly say that I'd prefer that my daughters did.
« Last Edit: November 23, 2012, 07:08:30 AM by Kiwi »
Don't criticize what you can't understand. — Bob Dylan, “The Times They Are A-Changin'” (1963)
Some people think they are thinking when they are really rearranging their prejudices and superstitions. — Edward R. Murrow (1908–65)

Offline Noldi400

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Re: Perception
« Reply #26 on: November 23, 2012, 11:56:24 AM »
Quote
There certainly aren't many HBs who get it, just as there aren't many HBs who think to pause and spend a few seconds laying straightedges along the “parallel” shadows that Bennett and Percy show them on page 22 of “Dark Moon” and in their video, or the shadows that Sibrel shows them in his video, “A Funny Thing Happened on the Way to the Moon.”  I suppose that the few who do have the brains to check don't claim the moonlandings are hoaxed because they already  know that they've been taken in by people who deal in terminological inexactitudes.

There's something else that a lot of people - HBs and otherwise - don't seem to understand that affects lunar shadows and a host of other things.

Anyone who has spent much time in a desert area is probably aware that while a surface can look relatively flat and level, when you begin to traverse the terrain it's likely to be very uneven; the combination of the nearly monochromatic surface and bright sunlight (with few shadows) tends to conceal the irregularities.

Looking at the images the astronauts took of the lunar surface, it mostly looks even, so when shadows - which of course follow the terrain - go in different directions, it just looks strange to the eye.
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Offline Sus_pilot

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Perception
« Reply #27 on: November 23, 2012, 12:32:22 PM »
(Hitchcock and his cinematographer used this to remarkable effect in Vertigo by trucking the camera and changing the focal length of a zoom lens at the same time...

Dollying.  Trucking is moving left or right, relative to the optical axis.  Dollying is moving forward or backward along the optical axis.  The cinematography term for this is simply the "dolly zoom," although it was referred to briefly as the "Spielberg zoom" when I was studying cinematography because the prevalent example of it had become Jaws.  It's even a pre-programmed macro in some motion-control systems.

But yes, the proper distance from the subject versus the focal length is something you study also in still photography to properly compose a portrait and to properly manage the depth of field and focus.  And you must be consciously aware of how the camera renders the impression of relative distance versus how your eyes perceive it.  That it is typically unconscious in most people is how the dolly zoom achieves its unsettling effect.

Don't ask me where I got trucking. I knew it was dolly.

Offline gillianren

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Re: Perception
« Reply #28 on: November 23, 2012, 02:09:23 PM »
Does anyone know exactly where that scene is in Jaws?  From memory it's a shot of Roy Scheider sitting on the beach and he realises the shark is starting to "bother" people close to shore, round about the time that a dog disappears.

I think so, but I haven't seen it in a while.  Honestly, I think I've seen Vertigo more recently.

Quote
The DVD of Vertigo has been selling here for around $10 recently, so I must grab it.  Maltin says it's a great film, and it lingered in my memory for a few years.

Yes, I believe it's one of Roger Ebert's Great Movies.  And I trust Roger more than I trust Maltin, who's getting to be a bit of a corporate shill these days.  Commentary tracks are one thing, but Disney seems to have Maltin on retainer these days.  He hosts all of their fancy tinned box sets.  While wearing a Mickey Mouse lapel pin.
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Offline ChrLz

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Re: Perception
« Reply #29 on: November 24, 2012, 05:28:13 AM »
Even further offtopic..)
...effects as wide-ranging as the Moon-tilt 'illusion'...
Haven't heard of that one, but I do know about the "gigantic" full moon as it rises behind a hill or distant trees.
It's my personal favorite..  Pick a time when both Moon and Sun are in the sky but are a reasonable distance apart,  around sunrise or sunset. Look at the angle from which the Moon is illuminated and mentally draw a straight line back to where the Sun *should* be...  It misses by a significant margin!  (which to some tinfoilhatters is proof that the sky/sun/moon is a hologram..  It's really quite a weird effect if you've never seen it before.

The reason for the 'illusion' (it isn't really an illusion at all) is simple perspective distortion - the same thing you get when standing near and beneath that long straight wall or standing on railway lines, the same thing that causes (anti-) crepuscular rays to fan out from the sun overhead and yet re-converge at the vanishing point on the opposite horizon.  Apart from those that run along the horizon and those directly overhead, those rays *cannot* be straight lines *from our viewpoint* - after all, they go from the two vanishing points spread by 180 degrees, but then fan outwards up to 45 degrees as they go over your head - no straight line could do that... :P

But yes, of course the light rays do follow a straight line in 3d reality - it is the projection of that straight line on our 'spherical' - yet 2d - viewpoint that causes the curve (and it's a real curve..).  I've probably described that badly, but it's hard to express in words..

Interestingly, the effect vanishes ('shifts' is a better word) if you alter your 'horizon' to match any curved ray, but by doing so, the actual horizon now becomes bent...  The fascinating thing is that because we *always* perceive the horizon as level and straight, your brain doesn't like doing that and will do its best not to let you perceive the curve.
« Last Edit: November 24, 2012, 05:34:38 AM by ChrLz »