November 28, 2014, 08:13:45 PM

### Author Topic: timelapse. how they do this  (Read 5788 times)

#### rambarra

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##### timelapse. how they do this
« on: December 03, 2012, 05:20:25 AM »
trying to figure out but no clue

https://vimeo.com/54734715

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##### timelapse. how they do this
« on: December 03, 2012, 05:20:25 AM »

#### PhilippP74

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• Posts: 25
##### Re: timelapse. how they do this
« Reply #1 on: December 03, 2012, 06:51:24 AM »
Could be I'm missing your point, but here's what I would try:

Doing a 14s exposure already produced some short star trails on my night pictures, so going for an exposure time of 1-3 minutes should give you something comparable seen in the video.

The clip had a length of about 6s which at 25 fps is 150 frames. So in total something between 2h and 7h total shooting time.

To to timelaspe I'm using a hÃ¤hnel Giga T Pro II or http://dslrcontroller.com/ on my Android phone.

Hope this helps

#### rpt

• Canon EF 300mm f/2.8L IS II
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##### Re: timelapse. how they do this
« Reply #2 on: December 03, 2012, 07:00:46 AM »
My guess is that the person took a number of time lapse still shots. Say that variable is "l". To get the star trails, one needs to create a composite of a number of shots. Say that variable is "m". To run for "s" seconds, one needs say 25 * s composites. This is needed so that the frames do not look jumpy - jumping the whole length of the star trail...

Since it ran for 5 sec, we need 125 composites.
Since each composite is made up of "m" shots; if "m" = 5; composite 1 is made up of shots 1,2,3,4 and 5; composite 2 made up of shots 2,3,4,5 and 6 and so on till composite 125 is made up of shots 125, 126, 127, 128, 129 and 130. So "l" becomes 130. Now string the composites in a video editor and that should do it...

May be there is a simpler way though...

#### rambarra

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##### Re: timelapse. how they do this
« Reply #3 on: December 03, 2012, 07:43:19 AM »
I was just guessing that if you, for example, make consequential 30 sec long exprosures you will add a segment to the top and delete a segment from the tail of the trail and it won't be a smooth movement as seen here

#### rpt

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##### Re: timelapse. how they do this
« Reply #4 on: December 03, 2012, 07:48:31 AM »
I was just guessing that if you, for example, make consequential 30 sec long exprosures you will add a segment to the top and delete a segment from the tail of the trail and it won't be a smooth movement as seen here
Yup, that is why I think it is made of composites...

If you put a mouse pointer at the end of a trail, it seemed to me that the frame advance was about 1/5 th. the star trail length; hence my magic number of 5...

#### joshmurrah

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• Posts: 117
##### Re: timelapse. how they do this
« Reply #5 on: December 03, 2012, 08:49:38 AM »
I was just guessing that if you, for example, make consequential 30 sec long exprosures you will add a segment to the top and delete a segment from the tail of the trail and it won't be a smooth movement as seen here
Yup, that is why I think it is made of composites...

If you put a mouse pointer at the end of a trail, it seemed to me that the frame advance was about 1/5 th. the star trail length; hence my magic number of 5...

this, definitely.

It's something like this:  Take roughly 130, one second exposures.  Then it's a startrail of 1-30 for frame 1, frames 2-31 for frame 2, frames 3-32 for frame 3...repeated roughly 100 times for the 4 seconds of video.  Pretty cool effect but WOW tedious.
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#### rpt

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##### Re: timelapse. how they do this
« Reply #6 on: December 03, 2012, 11:47:35 AM »
I was just guessing that if you, for example, make consequential 30 sec long exprosures you will add a segment to the top and delete a segment from the tail of the trail and it won't be a smooth movement as seen here
Yup, that is why I think it is made of composites...

If you put a mouse pointer at the end of a trail, it seemed to me that the frame advance was about 1/5 th. the star trail length; hence my magic number of 5...

this, definitely.

It's something like this:  Take roughly 130, one second exposures.  Then it's a startrail of 1-30 for frame 1, frames 2-31 for frame 2, frames 3-32 for frame 3...repeated roughly 100 times for the 4 seconds of video.  Pretty cool effect but WOW tedious.
I am just plain lazy. So is there a software program to merge the individual exposures? Also, how did you arrive at the magic number of 32? BTW, I like 32 better than 5...

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##### Re: timelapse. how they do this
« Reply #6 on: December 03, 2012, 11:47:35 AM »

#### rambarra

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##### Re: timelapse. how they do this
« Reply #7 on: December 03, 2012, 12:57:13 PM »
I'm struggling with my head. It is not that simple. You must take into account also the velocity at which the stars are moving.
If you make a burst of 130 shots (one per second) how much will star move in 2 minutes? A little bit.. but not that much.

And if you make one shot ... then wait ... then make another shot then wait etc... you will end up having 130 intervalled shots, which will result in jumping footage...

I'm more prone to think that this is done via software during editing
« Last Edit: December 03, 2012, 12:59:25 PM by rambarra »

#### pardus

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##### Re: timelapse. how they do this
« Reply #8 on: December 03, 2012, 01:51:41 PM »
Way longer exposures, 30 sec or more and no delay between shots
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#### bvukich

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##### Re: timelapse. how they do this
« Reply #9 on: December 03, 2012, 02:32:34 PM »
Way longer exposures, 30 sec or more and no delay between shots

No.  The star trails overlap from frame to frame.  This is rolling sets of N frames stacked, like joshmurrah said.

#### rpt

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##### Re: timelapse. how they do this
« Reply #10 on: December 03, 2012, 02:52:26 PM »
Way longer exposures, 30 sec or more and no delay between shots

No.  The star trails overlap from frame to frame.  This is rolling sets of N frames stacked, like joshmurrah said.
+1000
Do you know of a software that would merge "n" images given their file paths?

#### bvukich

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##### Re: timelapse. how they do this
« Reply #11 on: December 03, 2012, 03:11:57 PM »
Way longer exposures, 30 sec or more and no delay between shots

No.  The star trails overlap from frame to frame.  This is rolling sets of N frames stacked, like joshmurrah said.
+1000
Do you know of a software that would merge "n" images given their file paths?

I'd write a shell script to do it.  In fact, I probably still have some image series' left from last time I did a star time lapse, so I'll slap something together tonight.  I'll share the scripts once I'm done.  They'll be for Linux, but should  be easily adaptable to a Mac.  Sorry Windows users.

#### rpt

• Canon EF 300mm f/2.8L IS II
• Posts: 2259
• Could not wait for 7D2 so I got the 5D3
##### Re: timelapse. how they do this
« Reply #12 on: December 03, 2012, 03:53:06 PM »
Way longer exposures, 30 sec or more and no delay between shots

No.  The star trails overlap from frame to frame.  This is rolling sets of N frames stacked, like joshmurrah said.
+1000
Do you know of a software that would merge "n" images given their file paths?

I'd write a shell script to do it.  In fact, I probably still have some image series' left from last time I did a star time lapse, so I'll slap something together tonight.  I'll share the scripts once I'm done.  They'll be for Linux, but should  be easily adaptable to a Mac.  Sorry Windows users.

Thanks

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##### Re: timelapse. how they do this
« Reply #12 on: December 03, 2012, 03:53:06 PM »

#### samsettle

• Guest
##### Re: timelapse. how they do this
« Reply #13 on: December 03, 2012, 04:27:59 PM »
Try using StarStax... software just for this.

http://www.markus-enzweiler.de/software/software.html

#### bvukich

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##### Re: timelapse. how they do this
« Reply #14 on: December 03, 2012, 08:27:45 PM »
I need to adjust the setting for enfuse, but this is what I have so far.  It blends the images, ramping up to whatever the max is (\$FILESPAN) then ramps back down at the end.

Code: [Select]
`#!/bin/bashFILESPAN=30NUMBEROFFILES=`ls img_*.jpg | wc -l`LOOPCOUNT=\$((\$FILESPAN+\$NUMBEROFFILES-1))for i in \$(eval echo {1..\$LOOPCOUNT})doCUTSTART=\$((\$i-30))if [ \$CUTSTART -le 1 ]; then CUTSTART=1;fiCUTEND=\$iif [ \$CUTEND -ge \$NUMBEROFFILES ]; then CUTEND=\$NUMBEROFFILES;fienfuse --output=eimg_\$i.jpg `ls img_*.jpg | cut -d'' -f\$CUTSTART-\$CUTEND`done`
I'll post something more final, which will also resize and make the movie later tonight.

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##### Re: timelapse. how they do this
« Reply #14 on: December 03, 2012, 08:27:45 PM »