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iPhone video enhanced by rolling shutter effect

By dpreview staff on Jul 15, 2011 at 18:09 GMT

A guitarist on YouTube has shot a video on his iPhone that elegantly demonstrates the 'rolling shutter' effect. It occurs because its CMOS sensor captures video one line at a time, so there's an increasing lag as it scans down the frame. This 'rolling shutter' effect of movement being displaced across each frame can also be seen in DSLR-shot movies. In this case the video has been rotated, so the effects of that delay run left-to-right, giving interesting (and pretty) jagged effects, particularly on the bottom 'E' string. (via 9to5Mac)


(video by justkylevids)

The effect can be seen more dramatically with the fast-moving rotor blades of this aircraft. In this instance (shot with the older iPhone 3G) the shooter rotates the camera, helping demonstrate the interaction between the direction of the sensor's scanning and the rotor blades' movement.


(video by yanksoccer117)

And here, being used in a distinctly lyrical way by Flickr user Felix_m, is an older video showing the same effect shot on the Canon 5D Mark II.

Comments

Total comments: 92
treepop
By treepop (Jul 23, 2011)

very cool

0 upvotes
Klipsen
By Klipsen (Jul 22, 2011)

Enhanced? There may be some subtlety that I as a non-native English speaker do not understand, but in what way is it enhanced?

0 upvotes
Eric Fossum
By Eric Fossum (Jul 21, 2011)

A well known effect of course, but I still like the guitar string example.
Wish I had tried that!

2 upvotes
lylejk
By lylejk (Jul 21, 2011)

Strings reminds me of an Oscilloscope (guess that was the point). Still pretty cool looking, but I can see that there would be a limit as to how fast an object can move and still get captured proper. :)

0 upvotes
inevitable crafts studio
By inevitable crafts studio (Jul 20, 2011)

i hope the staff found that on lunch break while writing reviews about the leica s2 , the pentax 645d and leaf digital backs :)

2 upvotes
SM7
By SM7 (Jul 19, 2011)

Btw -- I found this interesting article for the author of this piece of news.

http://www.engadget.com/2011/07/18/want-to-write-for-engadget-were-hiring-in-tokyo-japan/

Want to write for Engadget? We're hiring in Tokyo, Japan!

0 upvotes
mr_ewok
By mr_ewok (Jul 19, 2011)

dpreview really gets boring. that´s it.

don´t know what those "news" shall bring to photographers.

0 upvotes
Leafvein
By Leafvein (Jul 19, 2011)

Rock on DPReview. Its a camera, its artistic, it belongs here. How is this not inspiring?

1 upvote
AshMills
By AshMills (Jul 18, 2011)

Not hugely relevant to news of photography. Interesting however.

www.AshMills.com

0 upvotes
jmmgarza
By jmmgarza (Jul 18, 2011)

Enjoyed the "rolling effect" youtube videos. Ninety nine percent of the DSLR videos that I produce won't be subject to "obvious" rolling shutter effect.

On the subject of photography news... I understand that your site is devoted to consumer photography. You print the usual (suspect) press releases, offer excellent analysis of products and tag them with links (make money) to vendors.

This is your niche. Yes, I would love to see diverse articles relevant to photographers (high-end printers, studio lighting, and such), but that would require a larger staff to write, edit and manage this enterprise. As a writer and photographer with a journalism degree and practical experience I know this costs a lot of money. Yes, you can do this on the cheap with interns and self-promoters, but again, that isn't quality journalism. Yes, I understand why DPReview does (only) what they do.

4 upvotes
AbrasiveReducer
By AbrasiveReducer (Jul 18, 2011)

I guess this is interesting in an "RIT" kind of way (meaning a science experiment that results in images.) As for photo news, buried in this month's Pop Photo is a paragraph saying that PMA is dead for good--not rescheduled; not renamed; not folded into CES--just gone. This might seem insignificant to the general public but it pretty much spells out the state of the photo industry; digital cameras are just electronic gizmos and therefore should be sold like laptops or iPhones.

1 upvote
wavrydr
By wavrydr (Jul 18, 2011)

I think this site needs to find a new editor if they plan to be a news outlet for camera tech. Dpreview has an unmatched database and comparison shopping guide, but their news reporting is lackluster at best. They consistently miss or simply do not report on significant news in the world cameras and camera technology. Instead of wasting time on fluff pieces like this they should actually do some research and write about news worthy articles. For example, the camera industry is moving towards mirror-less SLR cameras. Why not use all the camera brain power they can conjure up and write a unique piece on that idea. I recently read an article about a company making a camera that will allow you choose the focus point in the photo after the photo is taken.

Bottom line, this is great site, but the news here is a waste of time really. They rarely update it and when they do it's nothing special that you couldn't find by reading gizmodo or any of the other tech blogs.

4 upvotes
ClickBoom
By ClickBoom (Jul 18, 2011)

I enjoyed this fluff

3 upvotes
SM7
By SM7 (Jul 19, 2011)

Before the Amazon purchase, DPReview actually did camera reviews and did not post silly articles about phones with cameras (especially Apple products). However, it appears that it is now trying to compete directly with engadget, gizmodo, etc.

This article is not something I would have ever expected on a "pro" site like DPR. It's sad that my worst fears after the Amazon purchase are coming true. :(

It'd be nice if more REVIEWS of cameras and lenses were posted. Maybe a few less "previews", which seem to have taken over.

I find that I visit this site less and less (it used to be a permanent tab in my browser), due to the above.

4 upvotes
Pat Cullinan Jr
By Pat Cullinan Jr (Jul 18, 2011)

Dear DPReview,

I offer the following criticisms in a constructive sense. Please do not take them amiss.

First, this item doesn't belong on the home page with the camera news, but not for the reason you might imagine. The reason is that it lends a touch of unprofessionalism to the entire operation.

Secondly, the sample photos offered for this or that camera include pictures of young men in saloons. This also lends a touch of unprofessionalism, only a more serious one in this case. In any case, a blazer or a cardigan would do much to relieve the negative effect. It's all about image.

I reply on DPReview for the very best in review and news, and I sincerely thank you for all your efforts. You have been a major help to me in my photographic life.

Kindest regards,

Patrick Cullinan, Jr.

0 upvotes
willbfree
By willbfree (Jul 19, 2011)

Is there a Poll function to survey the question of whether the above is, or is not, tongue-in-cheek?

0 upvotes
shnsea
By shnsea (Jul 18, 2011)

Color blotch is correct. See this detailed explanation:
http://blog.alexbeutel.com/135/image-aliasing-of-plane-propellers-in-photos-and-video/
and for a better example:
http://www.youtube.com/watch?v=LVwmtwZLG88&feature=related

0 upvotes
Trevor G
By Trevor G (Jul 18, 2011)

Sorry guys, but this looks like a massive con job.

1) IF the electronic shutter in an iPhone functioned in such a way that it would resolve the vibrations of a guitar string, it could only resolve one such string, because each string has a different frequency.

It might be able to resolve a particular harmonic frequency common to all strings, but I have serious doubts that that would be possible, too.

2) When the phone is placed inside the guitar the fingers, strings the bearded guy and the background are all out of focus - when the music starts the strings, the fingers and the background are all amazingly sharp. That's amazing DOF, if nothing else!

3) Check the light along the edges of the strings pre-music, with the way the light no longer "surrounds" the strings with-music.

4) The skin colour of the fingers is clearly visible when inserting the phone and switching it on, but they suddenly become stylised, sharp, black and colourless once the music is played.

0 upvotes
Trevor G
By Trevor G (Jul 18, 2011)

5) The light across the edge of the sound hole remarkably stays the same in both instances, even though the light elsewhere changes dramatically.

0 upvotes
Ansel Spear
By Ansel Spear (Jul 18, 2011)

The reason the skin colour is visible at the outset is because light is falling on the hand. When playing, they're in the shadow.

The rolling shutter is not resolving harmonic frequency, it's simply doing its job - and filming. It would be quite odd if a camera couldn't film a 100 meter sprint because all runners were moving at a different speed.

0 upvotes
astromac
By astromac (Jul 18, 2011)

Trevor G seems to belong to the same category of "skeptics" as those who don't believe NASA actually went to the moon.
Another example of disbelief based on lack of knowledge and/or understanding would be if you thought that photo-finish photographs must be fakes, because the runners cannot have such weird arms or legs.

1 upvote
inevitable crafts studio
By inevitable crafts studio (Jul 20, 2011)

nasa DID went to the moon but not ON the moon, that was filmed by stanley kubrick as we all know :)

0 upvotes
inevitable crafts studio
By inevitable crafts studio (Jul 17, 2011)

boring times for photographic news i guess hehe

1 upvote
Russell Dawkins
By Russell Dawkins (Jul 17, 2011)

This begs the question - what do you and others easily bored, like patcam7122 below, *not* find boring? Why do you bother commenting - to prove your lofty standards?

3 upvotes
nosnoop
By nosnoop (Jul 17, 2011)

Russell: Maybe you should re-read that two postings again. Neither of the posters claimed that *this* particular new item is boring. They merely speculate that it must have been a slow news day with nothing much to report; and that the dpreview editors need to include this marginally related item as "news".

IMHO, I also find this "news" item out of place in dpreview's "News Update". Just click through news, and glance through the last 100 or so news headlines, and you would know what I mean.

0 upvotes
Fredella
By Fredella (Jul 18, 2011)

iPhone that elegantly demonstrates the 'rolling shutter' effect. It occurs because its CMOS sensor captures video one line at a time, so there's an increasing lag as it scans down the frame.

0 upvotes
mjkerpan
By mjkerpan (Jul 17, 2011)

The Iphone may have a better-than-average camera, but it's clearly still not very good for fast-motion video. Still, it's always nice to see somebody taking a technical flaw and using it to create interesting art. I love the "waveform" guitar strings!

0 upvotes
Nemesis2001
By Nemesis2001 (Jul 17, 2011)

It's a subsampling, so video aliasing effects occurs. It's clear from the guitar video, every string has a different vibration frequency. The real vibration frequency of the higher than the acquisition capability of the device, so the effect of aliasing is to show a perceived frequency that is 'scaled down' in respect of the original one, so scaled that is possible to see it clearly. Nice :)

1 upvote
Lutz - Luigi Gallerani
By Lutz - Luigi Gallerani (Jul 16, 2011)

All bad camera, like webcams, have this problem, nothing special in my opinion.

Another nice effect is to shoot a CRT screen with fast shutter speed (any camera can do this) and see only a small portion of the image in the screen, the rest is black.

It is the classical STROBOSCOPE problem....

0 upvotes
patcam7122
By patcam7122 (Jul 16, 2011)

Must have been a really boring news day in the photo world to even consider posting this "information"; never mind all the people who found it necessary to argue about what it all meant. Just another example of the Facebook-Twitter syndrome, I guess.

2 upvotes
vedat aslan
By vedat aslan (Jul 16, 2011)

on canon camera it occurs when shutter speed is faster than 1/4000 second. not because of frame rate. at high sutter speed camera can show you the string's vibration. but on iphone perhaps it is about a problem. because rotor blades change while rotating the iphone. i know that rolling shutter occurs while shifting the camera fastly. is there anyone that can explain the rolling shutter effect in detail?

0 upvotes
Lilianna
By Lilianna (Jul 16, 2011)

Cool effect, however ALL camera phones will do the same thing, this is not an Apple Innovation.

0 upvotes
JMartinP
By JMartinP (Jul 16, 2011)

CCDs with electronic shutter can't do it

0 upvotes
JMartinP
By JMartinP (Jul 16, 2011)

Sorry about that. Getting obsessed with proving everyone wrong here. You're right, almost all camera phones have uses CMOS sensors

0 upvotes
Ansel Spear
By Ansel Spear (Jul 18, 2011)

It's a CMOS shutter phenomenon, nothing to do with Apple. per se.

0 upvotes
DigitalDon
By DigitalDon (Jul 16, 2011)

Awesome camera position/capture. As a musician, I've often wished I could climb inside my instrument (generally, after making a mistake)! Great illustration.

0 upvotes
itsastickup
By itsastickup (Jul 16, 2011)

Not quite understanding why this is an 'enhancement' except perhaps using the most pure and virtuous marketing logic.

1 upvote
liin
By liin (Jul 16, 2011)

super cool

0 upvotes
Peter G
By Peter G (Jul 16, 2011)

There are science demos of similar that don't even need cameras:

http://www.youtube.com/watch?v=YGcAGaOUs9w

While this was shot on camera, the point of this one is you see it real time, in person without a camera frame rate interacting with the frequency of the sine waves on the strings, the strobe effect of the background does a similar thing.

While rolling shutter may have played a small part. The biggest part that lets you see the waves in the first place if frame rate interaction effect.

1 upvote
JMartinP
By JMartinP (Jul 16, 2011)

Haha, what you showed is essentially a demonstration of a rolling shutter! If the string were instead illuminated by a stroboscope, you'd only see a slowly moving slightly bent string

0 upvotes
RichardBalonglong
By RichardBalonglong (Jul 16, 2011)

This is interesting, and an artistic advantage on a disadvantage of a digital video. =)

0 upvotes
Kiril Karaatanasov
By Kiril Karaatanasov (Jul 16, 2011)

ok this is misleading the cool effect of having sine is not due to rolling shutter at all.

On may blame rolling shutter for the distorted sine in the lowest string, though I think the cause is again in how different frequencies combine to produce something not seen.

0 upvotes
JMartinP
By JMartinP (Jul 16, 2011)

Please see Color Blotch's comment below. the effect indeed appears due to the rolling shutter of the CMOS sensor (in combination with very short exposure time)

0 upvotes
luxvenator
By luxvenator (Jul 16, 2011)

Color Blotch's comment is wrong, see my reply to him

0 upvotes
JMartinP
By JMartinP (Jul 16, 2011)

Please see my reply to yours.

0 upvotes
JMartinP
By JMartinP (Jul 16, 2011)

Here's what the string looks like wo the rolling shutter effect. She shape is nowhere near what you see in the iphone movie.

0 upvotes
JMartinP
By JMartinP (Jul 16, 2011)

Sorry, heres the link: http://www.youtube.com/watch?v=wSQ9wr32v1k&feature=related

0 upvotes
JMartinP
By JMartinP (Jul 16, 2011)

Man, i should get back to work...
http://xkcd.com/386/

0 upvotes
Kiril Karaatanasov
By Kiril Karaatanasov (Jul 17, 2011)

You are showing high speed video of a string....there is no way to see frequency interference effects with high speed video.....this is becoming very unproductive discussion

0 upvotes
Kiril Karaatanasov
By Kiril Karaatanasov (Jul 17, 2011)

You are showing high speed video of a string....there is no way to see frequency interference effects with high speed video.....this is becoming very unproductive discussion

0 upvotes
JMartinP
By JMartinP (Jul 17, 2011)

Ok, I'll try to be clear. The wavy shapes of the strings are due to the rolling shutter and not their real shapes. The real shape of a vibrating guitar string can be seen in the vid I posted. I'm not sure what "cool effect" you're referring to in your original post but what I found striking in the vid was how the rolling shutter effect was elegantly used to show the time evolution of the strings. This can be seen in every separate frame and is not dependent on the framerate of the cam or the oscillating freq of the string.

0 upvotes
itsastickup
By itsastickup (Jul 16, 2011)

It's not news because it's been known for a long time and was visible when the very first 5DMKII vids came out.

2 upvotes
photohounds
By photohounds (Jul 16, 2011)

Not exactly news all right, but fun, nonetheless. First noticed with the first focal plane shutter cameras of about 90 years ago.

That effect is probably WHY cartoonists drew the wheels of a racing car sloping forward.

Example here: http://en.wikipedia.org/wiki/Automobilwerk_Eisenach

3 upvotes
AbrasiveReducer
By AbrasiveReducer (Jul 18, 2011)

There's a famous photo by Lartigue of a bicycle that every photo student knows (or should) with the elongated wheels. To me, the real "news" is how many people find the quality of cell phone cameras more than adequate.

0 upvotes
role_of_72
By role_of_72 (Jul 16, 2011)

This 'effect' is funny. :)

The other funny thing is if this was discovered in some other product it'd be a serious engineering mistake. But since it is in the iPhone this is fun and a killer feature.:D Apple has always been good in marketing.

0 upvotes
Enginel
By Enginel (Jul 16, 2011)

Every focal-plane shutter camera has this 'mistake'. In first Leicas, it took about 1/25 sec for curtain to travel across frame

1 upvote
role_of_72
By role_of_72 (Jul 16, 2011)

Yes, I know about the effect in cameras but there are differences between the two cases we talked about:

- the article is about _video_ recording, you mentiones _still_images_

- the effect is caused by the reading of data out of the CMOS _sensor_, the leicas (and other cameras) has it because of the _shutter_.

These two things make them really different from each other.
And I said that it is _fun_ and would like to add that this is _nothing_serious_ since it is in a mobile phone not in a professional camera (I don't know much about them anyway..).

0 upvotes
kishork
By kishork (Jul 16, 2011)

this is news because for many like me this is news... and its nice to know..

0 upvotes
ponvenkat
By ponvenkat (Jul 16, 2011)

Great idea of justkylevids using iphone and excellent imagination to use videography for teaching the frequency to students. Plane propeller shot by yanksoccer117 is also excellent

0 upvotes
keithwwalker
By keithwwalker (Jul 16, 2011)

I have a similar effect with my GF1, complements of Taiwan's bullet train:
http://vimeo.com/7533628

0 upvotes
straylightrun
By straylightrun (Jul 16, 2011)

How is this news?

2 upvotes
pannumon
By pannumon (Jul 16, 2011)

I find it (surprisingly) annoying that this is labeled as 'misc news'. I had no problems at all if it was labeled as 'misc' or 'on other sites'.

There could be a setting where users could define/priorize which kinds of stories are shown in the front page. Then nobody should complain.

Anyway, the effect is nice.

0 upvotes
D1N0
By D1N0 (Jul 16, 2011)

Because the rolling shutter bug turns out te be a feature ;). Typical for Apple ofcourse.

1 upvote
Aleo Veuliah
By Aleo Veuliah (Jul 16, 2011)

Amazing the first one

0 upvotes
BPJosh
By BPJosh (Jul 16, 2011)

The top video is awesome!

1 upvote
BPJosh
By BPJosh (Jul 16, 2011)

The top video is awesome!

2 upvotes
Patco
By Patco (Jul 16, 2011)

You can say that again!

1 upvote
Thomtek5
By Thomtek5 (Jul 16, 2011)

<table style="width:auto;"><tr><td><a href="https://picasaweb.google.com/lh/photo/z_eB82xqDKgTeIzcD8KGXA?feat=embedwebsite"><img src="https://lh4.googleusercontent.com/-uulKClW0RQ8/TFuSr7oVOMI/AAAAAAAACd4/MH5Tdhq7X8Y/s144/IMG_0001.JPG" height="108" width="144" /></a></td></tr><tr><td style="font-family:arial,sans-serif; font-size:11px; text-align:right">From <a href="https://picasaweb.google.com/ThomTek5/20100803?authuser=0&feat=embedwebsite">2010-08-03</a></td></tr></table>
That explains the odd effect i got with this pic.

0 upvotes
Jogger
By Jogger (Jul 15, 2011)

DPR is becoming a site for Apple fanboys. How come you dont cover Android or other platforms. Its all freaking apple all the time.

4 upvotes
Richard Butler
By Richard Butler (Jul 16, 2011)

We'd have posted this if it'd been shot on an Android phone, too. It just so happens that it wasn't.

0 upvotes
SM7
By SM7 (Jul 19, 2011)

IMHO "news" like this should not be posted on a site like DPR, regardless of the _phone_ it came from. I thought this was a reputable Photography Review site.

Come on guys, please do some real _reviews_!!! This is truly lame. :(

0 upvotes
bodziu
By bodziu (Jul 15, 2011)

Thanks for this news, I can feel the new dp spirit;-) More like this please! Now when you are in the fancy part of the world Gizmodo guys could drop you an interesting story and I am sure that both sites could benefit;)
Probably a few years ago mobile cameras and apps were not 'serious enough' to be mentioned here and maybe it was the reason that the dp home page did not even need refreshing as day after day the same bloody articles appeared (though in most cases interesting).

dp forums are updated by an average user of main camera brands at least every 10 minutes and for the mainstream brands it's every minute I suppose. Therefore I personally concluded that you guys must be simply lazy... or due to the outdated site architecture, new content publishing process was such a pain in the neck that your admin needed a few days to recover from this experience.

0 upvotes
bodziu
By bodziu (Jul 15, 2011)

In my opinion such 'light' news or interesting photography related (fair enough - in most cases useless) facts can co-exist with 'professional' camera news, reviews (which included priceless burst mode sounds in mp3) or guides like the HDR one.

I am sure that articles like this are a move in a good direction. At least in my case, waiting for a new review or more 'serious' article will no longer be like some painful experience of reading the same article about bloody FW update for camera I never hold in my hand, again and again...
Saying that, I'll contradict myself now admitting that I am quite disappointed with the number of news about movies in general. This is a bloody PHOTOGRAPHY site!
Yes, movie mode is in almost every camera (my has even bloody dedicated button which cant be disabled and I keep pressing it by accident) but you guys excel in *photography* and leave it like that... please!

0 upvotes
Richard Butler
By Richard Butler (Jul 15, 2011)

In which case I suspect I will continue to delight and infuriate you in equal measure over the coming months.

0 upvotes
SM7
By SM7 (Jul 19, 2011)

I imagine that as a result you'll gain some of the gizmodo crowd, lose the photography crowd. :(

0 upvotes
bodziu
By bodziu (Jul 20, 2011)

I don't think it's something dp should worry about. Where would the crowd go instead?
But agree to some extent, some people like the things the way they are and have always been, any change will bring an element of 'panic' ;-)
I can see it from some 'pro' photographers reaction on the camera's design changes, mainly in mirror-less segment where lack of dedicated ISO button, not mentioning EVF is simply too much ;-)

0 upvotes
Color Blotch
By Color Blotch (Jul 15, 2011)

No kind of " interaction between the vibration frequency of the strings and the frequency of the video capture" can produce such asymmetrical effects on strings. Regardless of capture frequency, any single stopped frame shot by a camera that captures the image as a whole represents the actual shape that string has at that particular moment. A camera without rolling shutter effect would have captured strings as slightly curved lines. No kind of complex "oscilloscope-like" shapes actually run through strings, those are capturing effects caused by the fact that upper lines of the image represent different moment of time than the lower ones.

10 upvotes
Michal59
By Michal59 (Jul 15, 2011)

Ditto.

0 upvotes
random78
By random78 (Jul 16, 2011)

Thats a good point. I think you are right.

0 upvotes
JMartinP
By JMartinP (Jul 16, 2011)

+1

0 upvotes
luxvenator
By luxvenator (Jul 16, 2011)

The strings actually move in that "asymetrical" way. Strings and any other resonating object vibrate in many harmonic frequencies at the same time, and the actual shape of the string at any given time is the result of the addition of all those harmonics, resulting in the shapes you see. That's what's called timbre, and is what makes a guitar, a flute a trumpet and a violin sound different even if they are playing the same note, what is called the harmonic content.

The iphone video's effect has nothing to do with the rolling shutter, but on the actual capture of the string's shape at any given time, and the shape moving left or right is the effect of the phase difference between the string's vibration and the camera's frame rate, you would see the same effect if you lighted the strings with a stroboscopic light with the same frequency and burst duration of the camera.

1 upvote
luxvenator
By luxvenator (Jul 16, 2011)

There are many videos on youtube where you can see the waveshape of guitar and other instruments:

http://youtu.be/ahAMEnOC2KU
http://youtu.be/D3UG6lOaxnM
http://youtu.be/J6fBmO0MCaw
http://youtu.be/J6fBmO0MCaw

0 upvotes
JMartinP
By JMartinP (Jul 16, 2011)

What you see on the oscilloscope screen is not the shape of the string at a time instant but rather the time evolution of the position of the string (which gives rise to teh sound wave). The effect of the rolling shutter is similar to the oscilloscope: what you see is the time evolution of the position of the string during the exposure of each frame.

There's also the stroboscopic effect: is causes the string to appear stationary if the oscillation frequency is a multiple of the framerate and slowly moving if its close to a multiple.

0 upvotes
Color Blotch
By Color Blotch (Jul 16, 2011)

@luxvenator
I suggest you to make a simple experiment: stretch out your arm, keep it straight, then start waving it in the air, smoothly, 1 complete cycle a second. If you also take a piece of ferromagnetic material in your hand and put a coil under it you can actually pick the signal of that motion with an oscilloscope. This signal will obviously be a 1 Hz sine wave. Now a question: do you think your arm shapes as a sine wave when you do all the above? If no, why do you think a guitar string should do that. If yes, you better see a physician soon.

1 upvote
jsandjs
By jsandjs (Jul 17, 2011)

http://140.117.166.1/eehome/ISCOM2005/SubmitPaper/UploadPapers/ISCON05_00159.pdf

0 upvotes
luxvenator
By luxvenator (Jul 17, 2011)

@JMartinP, so you mean the whole string moves as a whole, all of it goes to one direction of the other, the only standing wave is that of the fundamental tone, so there are no nodes, vibration modes and standing waves of harmonics?. You have just changed acoustics principles for ever.
@Color Blotch, a string doesn't produce a sine wave, but the sum of many sine waves which are the harmonics of the fundamental tone, my arm is not flexible enough to do that. Maybe my granny's would, it's very wobbly :-)
If the shutter speed is high enough you'll see the harmonics, if not they would blur out and you'll only see the fundamental and believe the string moves as a whole. It doesn't.

0 upvotes
Color Blotch
By Color Blotch (Jul 17, 2011)

Sure, it doesn't. There's actually a mysterious physical process that transforms string vibrations into a progressing wave that also matching the shape of the oscilloscope graph. And the proof of that is because you say so, how could it not be true, right? And in this video

http://www.youtube.com/watch?v=wSQ9wr32v1k

this isn't visible only because 1000fps is too slow of capturing speed. It's not for no reason that iPhone is widely known as a shutter speed champion.

0 upvotes
KARX
By KARX (Jul 15, 2011)

And now who said that the DSLRs are the best for capturing the video? Oh yes I've lost some creativity effect in my SONY HDR-XR520.

0 upvotes
random78
By random78 (Jul 15, 2011)

I thought exactly the same as peter. The effect in the guitar video seems to be due to interaction between the vibration frequency of the strings and the frequency of the video capture. Essentially a recreation of a high-school physics experiment. Does not seem to have much to do with the rolling shutter

0 upvotes
Peter G
By Peter G (Jul 15, 2011)

It doesn't look like rolling shutter effect to me (on the guitar).

Just the result of frame rate interacting with periodic motion of the strings.

2 upvotes
sherwoodpete
By sherwoodpete (Jul 15, 2011)

Well, there are two separate effects occurring here.

In any individual frame, it is the rolling-shutter effect which causes the odd jagged shapes.

On the other hand, when watching the video, we watch a sequence of frames in rapid succesion and the relationship of the frame rate to the string vibration frequency plays a part. This is visible in the video, where some of the time the strings appear to move slowly and can be observed easily, while at other times successive frames differ completely, giving a rapid motion which is impossible for the eye to follow.

1 upvote
Cy Cheze
By Cy Cheze (Jul 15, 2011)

DSLR owners can now proudly point to this video as an illustration of the charm of the "rolling shutter effect." Any CCD or 60p videocam that fails to show this distinctive trait in its clips can therefore be ridiculed:

No RSE, then not for me.
Jello is mellow.
More wobble, please.

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