# Time Lapse Photography Questions



## AquaStudent (Jan 4, 2011)

Hello TPT,

I just picked up my first "real" camera, a Nikon D5000, and have been experimenting with it over the past few months. I would really like to get into time lapse photography because I believe it would add greatly to my aquarium photography and especially my astrophotography/landscape photography.

Today I shot my first attempt at a timelapse and am working on editing. I don't have any software better than Windows Movie Maker at the moment but I'm working on getting something better.

I have heard of the term "Frame Dragging" but am not really sure what it means nor how to do it. From my naiive understanding I believe it helps restore a sense of speed in time lapse photography without creating sudden/spastic movements in the image by blurring together the motion. How can I create this effect?

Also, if you have any photography suggestions in general I would love to hear them. I will be uploading my timelapse once I have it rendered (hopefully I can get it to be semi-decent in WMM)


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## GraphicGr8s (Apr 4, 2011)

Frame-dragging may be illustrated most readily using the Kerr metric, which describes the geometry of spacetime in the vicinity of a mass M rotating with angular momentum J

c^{2} d\tau^{2} = \left( 1 - \frac{r_{s} r}{\rho^{2}} \right) c^{2} dt^{2} - \frac{\rho^{2}}{\Lambda^{2}} dr^{2} - \rho^{2} d\theta^{2}

- \left( r^{2} + \alpha^{2} + \frac{r_{s} r \alpha^{2}}{\rho^{2}} \sin^{2} \theta \right) \sin^{2} \theta \ d\phi^{2} + \frac{2r_{s} r\alpha c \sin^{2} \theta }{\rho^{2}} d\phi dt 

where rs is the Schwarzschild radius

r_{s} = \frac{2GM}{c^{2}} 

and where the following shorthand variables have been introduced for brevity

\alpha = \frac{J}{Mc} 

\rho^{2} = r^{2} + \alpha^{2} \cos^{2} \theta\,\! 

\Lambda^{2} = r^{2} - r_{s} r + \alpha^{2}\,\! 

In the non-relativistic limit where M (or, equivalently, rs) goes to zero, the Kerr metric becomes the orthogonal metric for the oblate spheroidal coordinates

c^{2} d\tau^{2} = c^{2} dt^{2} - \frac{\rho^{2}}{r^{2} + \alpha^{2}} dr^{2} - \rho^{2} d\theta^{2} - \left( r^{2} + \alpha^{2} \right) \sin^{2}\theta d\phi^{2} 

We may re-write the Kerr metric in the following form

c^{2} d\tau^{2} = \left( g_{tt} - \frac{g_{t\phi}^{2}}{g_{\phi\phi}} \right) dt^{2} + g_{rr} dr^{2} + g_{\theta\theta} d\theta^{2} + g_{\phi\phi} \left( d\phi + \frac{g_{t\phi}}{g_{\phi\phi}} dt \right)^{2} 

This metric is equivalent to a co-rotating reference frame that is rotating with angular speed Ω that depends on both the radius r and the colatitude θ

\Omega = -\frac{g_{t\phi}}{g_{\phi\phi}} = \frac{r_{s} \alpha r c}{\rho^{2} \left( r^{2} + \alpha^{2} \right) + r_{s} \alpha^{2} r \sin^{2}\theta} 

In the plane of the equator this simplifies to:[78]

\Omega = \frac{r_{s} \alpha c}{r^{3} + \alpha^{2} r + r_{s} \alpha^{2}} 

Thus, an inertial reference frame is entrained by the rotating central mass to participate in the latter's rotation; this is frame-dragging.


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## Da Plant Man (Apr 7, 2010)

I have the D5100 and I absolutely love the interval shooting mode it has. I can take photos timed from 1 second to one hour apart and take up to 999 photos on a set timer. Really handy


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## GraphicGr8s (Apr 4, 2011)

Da Plant Man said:


> I have the D5100 and I absolutely love the interval shooting mode it has. I can take photos timed from 1 second to one hour apart and take up to 999 photos on a set timer. Really handy


So the D5100 has an intervalometer built in? Cool.


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## Da Plant Man (Apr 7, 2010)

That went right over my head, Graphic.


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## GraphicGr8s (Apr 4, 2011)

Was just trying to answer the question.


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## Da Plant Man (Apr 7, 2010)

You could have just said 42. That is the answer to life, after all.


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## zainey_04 (May 24, 2011)

The D5000 also has an intervalometer built in.


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## AquaStudent (Jan 4, 2011)

GraphicGr8s said:


> Frame-dragging may be illustrated most readily using the Kerr metric, which describes the geometry of spacetime in the vicinity of a mass M rotating with angular momentum J
> 
> c^{2} d\tau^{2} = \left( 1 - \frac{r_{s} r}{\rho^{2}} \right) c^{2} dt^{2} - \frac{\rho^{2}}{\Lambda^{2}} dr^{2} - \rho^{2} d\theta^{2}
> 
> ...


I am a physicist  Nice try though.

HAHA 42!!!! Another great answer

Zainey I did use the interval timer. I'm just trying to figure out how to get better photos for the time lapse. I've seen lapses of city scenes for instance where the motion is blurred. I'm not sure if that effect is gotten simply by taking a longer exposure time or if there is some other trick


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## Da Plant Man (Apr 7, 2010)

Oh. Thats just long exposure. Your going to either want a shutter release remote, or have a delayed timer so you prevent vibrations for a sharper image. The camera has a delayed timer already. 30 secs I think is the max preset for the d5000, you can do bulb effect, where you hold the shutter button down. 


-Caton


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## AquaStudent (Jan 4, 2011)

Right but I also don't want the image to be washed out from light. perhaps it's just finding the right balance :/

I'll give that a shot the next time im out.

The next clear coursework-free night I'll be heading up to the observatory here (my third home...second being the physics study room) and trying a timelapse of the night sky.


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## Da Plant Man (Apr 7, 2010)

AquaStudent said:


> Right but I also don't want the image to be washed out from light. perhaps it's just finding the right balance :/
> 
> I'll give that a shot the next time im out.
> 
> The next clear coursework-free night I'll be heading up to the observatory here (my third home...second being the physics study room) and trying a timelapse of the night sky.



For daytime, you want to adjust the aperture to the smallest it can go (if its the kit lens, I am assuming 32). With F stops (aperture) the higher the number, the smaller the aperture. For the nights sky, you want to open it as much as possible, which is either 3.5 or 5.6 (or around that). Just try messing with that, and you should be able to figure it out. A good tripod is also recommended.


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## GraphicGr8s (Apr 4, 2011)

AquaStudent said:


> *I am a physicist*  Nice try though.
> 
> HAHA 42!!!! Another great answer
> 
> Zainey I did use the interval timer. I'm just trying to figure out how to get better photos for the time lapse. I've seen lapses of city scenes for instance where the motion is blurred. I'm not sure if that effect is gotten simply by taking a longer exposure time or if there is some other trick


You mean eventually you will be a physicist don't you? I've probably forgotten more about physics then what you're learning now. But I did manage to remember one class discussing relativity and frame dragging. Of course that class was 26 years ago and after I got my degree promptly did nothing with it. Unfortunately the formulas didn't copy over and I was way to lazy to do it by hand.

Anyhow:



> *Einstein's general theory of relativity predicts that non-static, stationary mass-energy distributions affect spacetime in a peculiar way giving rise to a phenomenon usually known as frame-dragging. The first frame-dragging effect was derived in 1918*, in the framework of general relativity, by the Austrian physicists Josef Lense and Hans Thirring, and is also known as the Lense–Thirring effect.[1][2][3] They predicted that the rotation of a massive object would distort the spacetime metric, making the orbit of a nearby test particle precess. This does not happen in Newtonian mechanics for which the gravitational field of a body depends only on its mass, not on its rotation. The Lense-Thirring effect is very small—about one part in a few trillion. To detect it, it is necessary to examine a very massive object, or build an instrument that is very sensitive. More generally, the subject of effects caused by mass-energy currents is known as gravitomagnetism, in analogy with classical electromagnetism.


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## AquaStudent (Jan 4, 2011)

GraphicGr8s said:


> You mean eventually you will be a physicist don't you? I've probably forgotten more about physics then what you're learning now. But I did manage to remember one class discussing relativity and frame dragging. Of course that class was 26 years ago and after I got my degree promptly did nothing with it. Unfortunately the formulas didn't copy over and I was way to lazy to do it by hand.
> 
> Anyhow:


Haha yes but image is everything (physicist sounds so much better than physics and mathematics dual major...it's so much of a mouth full. "physicist if all goes as planned" fits better but lacks alliteration.) Right now I'm an amateur astronomer and get to time travel to the past every clear night. I thought of some dimensional analysis, variable swapping, a Lorentz transformation, and one flux capacitor later I can travel forward in time.

A few things that all my physics and mathematics classes have taught me
1) Caffeine is a lifesaver
2) Never try to do math with a lack of sleep
3) Even ugly things can become pretty...you just have to look in the right way
4) When in doubt convert to moles...wait no that's Chemistry


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## Bahugo (Apr 18, 2011)

GraphicGr8s said:


> Frame-dragging may be illustrated most readily using the Kerr metric, which describes the geometry of spacetime in the vicinity of a mass M rotating with angular momentum J


Really should have sourced this instead of making it seem like you wrote it.

Edit: I am referring too the whole post, not just that one line just wanted too shorten it up.


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## AquaStudent (Jan 4, 2011)

Ok well I finally got a video rendered after taking about 4 hours to get my hands on VirtualDub (my un-zip software wasn't cooperating).

http://www.youtube.com/watch?v=up5h8UG3CGM

It's not great but has definitely taught me a lot.

Next time I would like to find an angle that doesn't have so much reflection, lower the lighting and take a longer exposure (blur motion as well), find a way to cover up the scratch/turn around my tank, and do some more tinkering in a video editing software so I can use my intro and fade the music.

It took 3 hours to render the video...ridiculous!


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## Da Plant Man (Apr 7, 2010)

Oh...that? Yeah... I thought you were wanting long exposure. My bad.


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## mistergreen (Dec 9, 2006)

Time lapse works best if you focus on slow moving things. And there are software things like frame blending that makes it looke extra smooth. They're found in sophisticated and expensive video editing software like after effects.


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## GraphicGr8s (Apr 4, 2011)

Bahugo said:


> Really should have sourced this instead of making it seem like you wrote it.
> 
> Edit: I am referring too the whole post, not just that one line just wanted too shorten it up.


It was a joke. AquaStudent got it. And the source was Wikipedia but it really doesn't matter. Sure,it's the actual formulas for frame dragging but who really cares? It was a joke. (Well, back in school I cared.)


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## AquaStudent (Jan 4, 2011)

I think the time lapse will work well enough if I increase the exposure rate. If I take 2x as many photos in half the time I'll get the same length video but smoother transitions. Longer exposures should also try blending the motion. I also need to decide if I want a blurry background (probably not) and adjust the aperture accordingly.

Since I don't have access to any fancy afterimage programs I'll just have to work with what I have. Thanks for the help Green.


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## mountaindew (Dec 10, 2008)

http://www.plantedtank.net/forums/tank-journals/85067-55-gal-aquascape-2-56k-stay.html
this shows a system over a 60 day period

2nd page shows short animation done by a member


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## AquaStudent (Jan 4, 2011)

that's cool! you gotta love gifs!


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## AquaStudent (Jan 4, 2011)

Here's another Time Lapse video I recorded this weekend. Let me know what you think.

It's still a bit choppy for my liking but it's much better. I wish I could render at higher than 5 fps or something... any suggestions on (free) time lapse rendering software? I'm trying to get my hands on lightroom...that should be accessible by the end of the week 

Anyway here's the video.

Time Lapse of 10 Gallon Peaceful Community


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## GraphicGr8s (Apr 4, 2011)

Nice clip. It may be a tad choppy but it's not shot like a movie. You'd need to be up around 24fps. It's good for what it is. A time lapse sequence.


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## AquaStudent (Jan 4, 2011)

Any ideas on how I can bump up the frame rate? I've been using Powerdirector and import the images and flash them as quickly as I can...but the fastest I can get is .2 seconds per image (which is far from 24 fps).

If I could get 15, 24, or 30 fps I could then drop the timer down to a much quicker rate (so .5 seconds between shots rather than 2 or 4 seconds) which will make it much smoother.

EDIT: and a short youtube search later and I may have found my answer


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