Time Lapse Settings--Boyd? at DVinfo.net

Chris Long · December 1st, 2003, 08:10 AM

Hi All
I was going to send an email directly to you, Boyd, since this is aimed at you, but thought maybe others could benefit as well. I was looking at the time lapse clip you have on your website (the vertical smear example) and was wondering what time lapse/interval settings you used to accomplish it. Was it done wholly in the camera, or did you mess with the timing in post, as well?

I realize it's hard to remember what the heck we did sometimes (is for me, at least) but a general idea is close enough for me. It's nice to see an example of what is possible before committing to a long shoot, only to find the results aren't optimal...

Thanks for any info you might have on the clip--anyone else have ideas about interval setting that work well?

Boyd Ostroff · December 1st, 2003, 09:11 AM

I didn't do anything with the camera. For time lapse sequences I think you are much better offer to tape as normal 60i, then change the speed in post. The only caveat would be if the sequence won't fit on a tape. I've done a lot of taping of sunsets, moving clouds, etc. and always shoot them in realtime. Some of them get sped up by as much as 1200% in post. At that speed you could fit about a 5 minute finished sequence on a tape (5 x 12 = 60). You will get much smoother action and have a lot more options shooting in real time. For example, I'm never sure exactly how much I want to speed something up until I get a chance to look at it.

Last year I did shoot one really long sequence where I let the camera run for about 12 hours overnight during a snowstorm. In that case I used the camera's interval setting where (IIRC) it shoots 1/2 second every 30 seconds. This is fine when you're really speeding things up a lot (I turned about 8 hours into 10 seconds), but will not give good results for things like sunsets.

Experiment around a little on your own and see what you think. It's a lot of fun, but you need to be patient!

Chris Long · December 1st, 2003, 10:12 PM

Thanks, Boyd. I do have to experiment more, that's for sure.

Not sure the realtime shooting will work for all of what I have in mind, though. Some shots it'd be good, I'm sure, but not for all. I want to do studies of light and motion in and around a building I work in (a public library) and I'd like to have long periods of time represented--I'd have to shoot a whole tape probably for each shot, and then I'm not sure if that would be enough, when sped up. I have no doubt it would be the smoothest way though, as you say.

Ideally, I think I'd do a frame capture thing with a laptop, but that's not a possibility right now. Gonna think about it all some more.

Thanks!

Boyd Ostroff · December 1st, 2003, 10:42 PM

Try running some numbers to get an idea of what to expect. I believe the minimum interval setting gives you a 1/2 sec burst of footage every 30 seconds. So you would get 1 second of footage for each minute of realtime. But since it's filming ~15 frames twice per minute, you're really only getting 2 unique frames per minute. Now for smooth motion your finished video should have 30 unique frames each second. In post you would have to speed up the interval footage by 1500% (eg: 2 frames per second x 15 = 30 frames). So in other words you would need to compress 15 minutes of real time into 1 second of finished video. If you aren't speeding it up this much there will be a certain jerky quality, which may or may not be a problem for you. For example, if you wanted to turn 5 minutes of footage into a 1 second sequence it would look like video That was shot at around 10 frames per second (2 fps x 5 = 10). Depending of the amount of movement this still might be fine though.

Yes, the laptop route would make the most sense probably. I bought a neat little shareware program called BTV Pro which can do this (although I've never used it for that; I got it as a way to turn my laptop into a portable video monitor via firewire). Unfortunately the program is only available on the Mac, but I've heard there are similar things for the PC.

Let us know what you end up doing and how it works out for you!

Graeme Nattress · December 2nd, 2003, 05:32 AM

Also, when the PDX10 says it's recording half a second - don't believe it! Count the number of frames - I found mine recorded exactly 17 frames per interval, which throws off your calculations somewhat.

If anyone's using FCP, I have a little plugin I can send you which will help with this kind of stuff...

Graeme

Boyd Ostroff · December 2nd, 2003, 09:03 AM

Thanks Graeme, I've never really looked into it that deeply. In fact I've never actually used the interval setting on the PDX-10, but have used it on my VX-2000 and it appears to be similar.

The calculations I gave were just an example of how you could "get your head around" the whole idea of time lapse. They shouldn't be considered anything particularly accurate. As I said earlier, in the end you will have to watch the footage and adjust the speed until it looks the way you like.

But the main point is that using the builtin interval timer is sort of a crude way to shoot timelapse and won't give you very nice results unless you're going to speed the raw footage up to compress hours into seconds. Plugging the camera into a laptop is a good solution but of course it's bulky and you will need to power the laptop externally for long captures.

So even if you have to use a full tape for each shot Chris it really may be your best option. Tape is pretty cheap, you don't need any external equipment, and you preserve the maximum flexibility when it comes time to edit. Of course one downside is that you will have to capture hours of footage into your computer just to get a short finished sequence. That's what I do however, and once I get a finished sequence edited down I just delete the big capture files.

Chris Long · December 2nd, 2003, 09:45 AM

Actually, the long capture times was one of my concerns, though I missed putting it into my original posts. I was leery of filming for a solid hour, then capturing into the computer for an hour.

At the same time, I have this feeling that the interval way of doing it (in-camera) might be a bit trying on the camera mechanism, too--all that off and on. So it might be 6 of one, 1/2 dozen of the other...

Thanks again--and thanks Graeme for the info in the frames--it's good that someone digs into this stuff and finds out what's what!

December 1st, 2003, 08:10 AM	#1
Chris Long Regular Crew Join Date: Jul 2003 Location: Middletown, Maryland USA Posts: 177	Time Lapse Settings--Boyd? Hi All I was going to send an email directly to you, Boyd, since this is aimed at you, but thought maybe others could benefit as well. I was looking at the time lapse clip you have on your website (the vertical smear example) and was wondering what time lapse/interval settings you used to accomplish it. Was it done wholly in the camera, or did you mess with the timing in post, as well? I realize it's hard to remember what the heck we did sometimes (is for me, at least) but a general idea is close enough for me. It's nice to see an example of what is possible before committing to a long shoot, only to find the results aren't optimal... Thanks for any info you might have on the clip--anyone else have ideas about interval setting that work well?

December 2nd, 2003, 05:32 AM	#5
Graeme Nattress RED Problem Solver Join Date: Sep 2003 Location: Ottawa, Canada Posts: 1,365	Also, when the PDX10 says it's recording half a second - don't believe it! Count the number of frames - I found mine recorded exactly 17 frames per interval, which throws off your calculations somewhat. If anyone's using FCP, I have a little plugin I can send you which will help with this kind of stuff... Graeme __________________ www.nattress.com - filters for FCP

December 1st, 2003, 09:11 AM	#2
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,802	I didn't do anything with the camera. For time lapse sequences I think you are much better offer to tape as normal 60i, then change the speed in post. The only caveat would be if the sequence won't fit on a tape. I've done a lot of taping of sunsets, moving clouds, etc. and always shoot them in realtime. Some of them get sped up by as much as 1200% in post. At that speed you could fit about a 5 minute finished sequence on a tape (5 x 12 = 60). You will get much smoother action and have a lot more options shooting in real time. For example, I'm never sure exactly how much I want to speed something up until I get a chance to look at it. Last year I did shoot one really long sequence where I let the camera run for about 12 hours overnight during a snowstorm. In that case I used the camera's interval setting where (IIRC) it shoots 1/2 second every 30 seconds. This is fine when you're really speeding things up a lot (I turned about 8 hours into 10 seconds), but will not give good results for things like sunsets. Experiment around a little on your own and see what you think. It's a lot of fun, but you need to be patient!

December 1st, 2003, 10:12 PM	#3
Chris Long Regular Crew Join Date: Jul 2003 Location: Middletown, Maryland USA Posts: 177	Thanks, Boyd. I do have to experiment more, that's for sure. Not sure the realtime shooting will work for all of what I have in mind, though. Some shots it'd be good, I'm sure, but not for all. I want to do studies of light and motion in and around a building I work in (a public library) and I'd like to have long periods of time represented--I'd have to shoot a whole tape probably for each shot, and then I'm not sure if that would be enough, when sped up. I have no doubt it would be the smoothest way though, as you say. Ideally, I think I'd do a frame capture thing with a laptop, but that's not a possibility right now. Gonna think about it all some more. Thanks!

December 1st, 2003, 10:42 PM	#4
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,802	Try running some numbers to get an idea of what to expect. I believe the minimum interval setting gives you a 1/2 sec burst of footage every 30 seconds. So you would get 1 second of footage for each minute of realtime. But since it's filming ~15 frames twice per minute, you're really only getting 2 unique frames per minute. Now for smooth motion your finished video should have 30 unique frames each second. In post you would have to speed up the interval footage by 1500% (eg: 2 frames per second x 15 = 30 frames). So in other words you would need to compress 15 minutes of real time into 1 second of finished video. If you aren't speeding it up this much there will be a certain jerky quality, which may or may not be a problem for you. For example, if you wanted to turn 5 minutes of footage into a 1 second sequence it would look like video That was shot at around 10 frames per second (2 fps x 5 = 10). Depending of the amount of movement this still might be fine though. Yes, the laptop route would make the most sense probably. I bought a neat little shareware program called BTV Pro which can do this (although I've never used it for that; I got it as a way to turn my laptop into a portable video monitor via firewire). Unfortunately the program is only available on the Mac, but I've heard there are similar things for the PC. Let us know what you end up doing and how it works out for you!

December 2nd, 2003, 09:03 AM	#6
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,802	Thanks Graeme, I've never really looked into it that deeply. In fact I've never actually used the interval setting on the PDX-10, but have used it on my VX-2000 and it appears to be similar. The calculations I gave were just an example of how you could "get your head around" the whole idea of time lapse. They shouldn't be considered anything particularly accurate. As I said earlier, in the end you will have to watch the footage and adjust the speed until it looks the way you like. But the main point is that using the builtin interval timer is sort of a crude way to shoot timelapse and won't give you very nice results unless you're going to speed the raw footage up to compress hours into seconds. Plugging the camera into a laptop is a good solution but of course it's bulky and you will need to power the laptop externally for long captures. So even if you have to use a full tape for each shot Chris it really may be your best option. Tape is pretty cheap, you don't need any external equipment, and you preserve the maximum flexibility when it comes time to edit. Of course one downside is that you will have to capture hours of footage into your computer just to get a short finished sequence. That's what I do however, and once I get a finished sequence edited down I just delete the big capture files.

December 2nd, 2003, 09:45 AM	#7
Chris Long Regular Crew Join Date: Jul 2003 Location: Middletown, Maryland USA Posts: 177	Actually, the long capture times was one of my concerns, though I missed putting it into my original posts. I was leery of filming for a solid hour, then capturing into the computer for an hour. At the same time, I have this feeling that the interval way of doing it (in-camera) might be a bit trying on the camera mechanism, too--all that off and on. So it might be 6 of one, 1/2 dozen of the other... Thanks again--and thanks Graeme for the info in the frames--it's good that someone digs into this stuff and finds out what's what!