Time Lapse Question at DVinfo.net

Milo Skinner · November 15th, 2005, 03:33 PM

Hello! I have a quick shoot this evening where I'll be filming a local intersection at rush hour. I'm going to shoot real-time (not interval recording mode), then speed up in post for a time-lapse effect.

I'm assuming I'll get the best look if I shoot in "frame mode" at 15fps progressive, rather than the standard 60i, since I'll avoid the low frame rate problem when I speed up in post (Vegas).

Is there any reason that I'm overlooking that I should use the standard 60i rather than frame mode?

TIA

Boyd Ostroff · November 15th, 2005, 03:59 PM

I've tried that for time lapse and it worked fine. There was sort of a harsh edge on things however which I assume had to do with fine details in the progressive frames. I didn't really take the time to examine closely since I didn't use the footage for anything. Check it out and let us know what you think of the results.

Milo Skinner · November 15th, 2005, 08:38 PM

Well I shot the footage today and, aside from me doing a poor job managing the light, I liked what I got. As a side note, if you need to do an intermittent render to raise the effective playback rate higher than the 12x Vegas does naturally, I think it looks best to do those as progressive renders as well, then move to 60i with the final output.

Thanks for the help.

John Cloy · November 16th, 2005, 09:10 AM

Milo - how long was the real time of the elapsed shot?

I need to play with time-lapse (which I have never used). My niece is getting married in my backyard at the end of the month and I was toying with the idea of setting up a camera on the roof at sunrise and capturing the yard setup up to the processional and then cutting to realtime as she walked down the aisle.

I thought it might be a fun shot for them to see the chairs, tables, capet runner, lights, guests arriving and being seated, etc...

Any hints that anyone has would be much appreciated...

jc

Milo Skinner · November 16th, 2005, 01:16 PM

John,

I only needed a 15-second (finished) piece, and I didn't need it super-fast, so I filmed for about 5 minutes. If I were doing it again, I might film for 10 or 15, just for more flexibility with how fast I could make the final product.

If you're going to set up and film several hours' worth of footage, that's obviously too long for a tape. One option (my personal preference) would be recording direct to disk. In that case, remember you'll need about 11 gigs (if I remember correctly) of HD space for each hour of footage. It's resources-intesive, both for storage and rendering down later, but it leaves you the most options.

If that's not viable, using the 170's "interval record" setting will probably be your next best bet. I've filmed some sunsets and clouds with that, and it works fairly well. I always use the setting that records a 1/2 second (approx 15 frame) burst every 30 seconds.

Because you are recording 15 frames per burst instead of 1, it won't be a smooth-looking shot until you increase the speed to 15x in post (effectively "crunching" each set up 15 frames into 1 frame). So, your final lapse-speed will be 2x (from recording only half-second bursts), times 30x (from shooting 1 burst per minute instead of 30), times 15x (from the rate enhancement in post to smooth out the jerkiness) for a total of 900x. At that rate, you'll view an hour's worth of activite every 4 seconds. That's about the "slowest" you can get smooth shots using the interval record function.

Of course, if you want a faster lapse, you can increase the time interval between bursts of recording. But I've found that 1 hour per 4 seconds is plenty fast if you want people to be able to understand what's happening at all.

Hope that helps. Anyone can chime in if I've messed up that math!

Brian Keith · November 21st, 2005, 08:50 PM

Did you shoot this during the day or at night? Curious as I was wondering if you picked up the "streaking" of headlights etc like you can get with a SLR 35mm with the shutter held open at night.

I haven't tried this yet but would like to at night for the streaking effect.

Milo Skinner · November 22nd, 2005, 11:42 AM

The shot was during the day.

With the interval recording, you won't get any steaking effect, because for the half-second that the camera is filming, the exposure settings aren't any different than they would be if you were just shooting normally. In addition, any streaking that you created from slowing the shutter would be effectively lost when you sped the footage up more in post.

You do get a little bit of motion blur as the NLE combines frames when you increase the playback rate. But it's not enough for that cool, artsy long exopsure look.

I have a shot I need that effect for, though, and have been thinking about how to get it. I think the best option would be a motion blur filter in post, after you have the shot up to your final speed.

Tom Hardwick · November 25th, 2005, 11:51 AM

You can't really get the same 'streaking headlight' effect with the VX/PD Brian. With a Super-8 film camera such as the Beaulieu you can expose each frame for 10 seconds, say, then immediately expose the next frame for 10 seconds and so on. On replay the headlights form one long stream on screen.

With our video cameras you can dial down to 1/3rd sec per frame, but the effect looks quite different simply because the shutter isn't open for long enough.

tom.

November 15th, 2005, 03:33 PM	#1
Milo Skinner New Boot Join Date: Apr 2005 Location: Eugene, Oregon Posts: 14	Time Lapse Question Hello! I have a quick shoot this evening where I'll be filming a local intersection at rush hour. I'm going to shoot real-time (not interval recording mode), then speed up in post for a time-lapse effect. I'm assuming I'll get the best look if I shoot in "frame mode" at 15fps progressive, rather than the standard 60i, since I'll avoid the low frame rate problem when I speed up in post (Vegas). Is there any reason that I'm overlooking that I should use the standard 60i rather than frame mode? TIA

November 16th, 2005, 09:10 AM	#4
John Cloy Regular Crew Join Date: Aug 2004 Location: Escondido, CA Posts: 50	Milo - how long was the real time of the elapsed shot? I need to play with time-lapse (which I have never used). My niece is getting married in my backyard at the end of the month and I was toying with the idea of setting up a camera on the roof at sunrise and capturing the yard setup up to the processional and then cutting to realtime as she walked down the aisle. I thought it might be a fun shot for them to see the chairs, tables, capet runner, lights, guests arriving and being seated, etc... Any hints that anyone has would be much appreciated... jc __________________ John You mean I can get paid to do this?

November 15th, 2005, 03:59 PM	#2
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,802	I've tried that for time lapse and it worked fine. There was sort of a harsh edge on things however which I assume had to do with fine details in the progressive frames. I didn't really take the time to examine closely since I didn't use the footage for anything. Check it out and let us know what you think of the results.

November 15th, 2005, 08:38 PM	#3
Milo Skinner New Boot Join Date: Apr 2005 Location: Eugene, Oregon Posts: 14	Well I shot the footage today and, aside from me doing a poor job managing the light, I liked what I got. As a side note, if you need to do an intermittent render to raise the effective playback rate higher than the 12x Vegas does naturally, I think it looks best to do those as progressive renders as well, then move to 60i with the final output. Thanks for the help.

November 16th, 2005, 01:16 PM	#5
Milo Skinner New Boot Join Date: Apr 2005 Location: Eugene, Oregon Posts: 14	John, I only needed a 15-second (finished) piece, and I didn't need it super-fast, so I filmed for about 5 minutes. If I were doing it again, I might film for 10 or 15, just for more flexibility with how fast I could make the final product. If you're going to set up and film several hours' worth of footage, that's obviously too long for a tape. One option (my personal preference) would be recording direct to disk. In that case, remember you'll need about 11 gigs (if I remember correctly) of HD space for each hour of footage. It's resources-intesive, both for storage and rendering down later, but it leaves you the most options. If that's not viable, using the 170's "interval record" setting will probably be your next best bet. I've filmed some sunsets and clouds with that, and it works fairly well. I always use the setting that records a 1/2 second (approx 15 frame) burst every 30 seconds. Because you are recording 15 frames per burst instead of 1, it won't be a smooth-looking shot until you increase the speed to 15x in post (effectively "crunching" each set up 15 frames into 1 frame). So, your final lapse-speed will be 2x (from recording only half-second bursts), times 30x (from shooting 1 burst per minute instead of 30), times 15x (from the rate enhancement in post to smooth out the jerkiness) for a total of 900x. At that rate, you'll view an hour's worth of activite every 4 seconds. That's about the "slowest" you can get smooth shots using the interval record function. Of course, if you want a faster lapse, you can increase the time interval between bursts of recording. But I've found that 1 hour per 4 seconds is plenty fast if you want people to be able to understand what's happening at all. Hope that helps. Anyone can chime in if I've messed up that math!

November 21st, 2005, 08:50 PM	#6
Brian Keith New Boot Join Date: Dec 2004 Location: US of A Posts: 20	Did you shoot this during the day or at night? Curious as I was wondering if you picked up the "streaking" of headlights etc like you can get with a SLR 35mm with the shutter held open at night. I haven't tried this yet but would like to at night for the streaking effect.

November 22nd, 2005, 11:42 AM	#7
Milo Skinner New Boot Join Date: Apr 2005 Location: Eugene, Oregon Posts: 14	The shot was during the day. With the interval recording, you won't get any steaking effect, because for the half-second that the camera is filming, the exposure settings aren't any different than they would be if you were just shooting normally. In addition, any streaking that you created from slowing the shutter would be effectively lost when you sped the footage up more in post. You do get a little bit of motion blur as the NLE combines frames when you increase the playback rate. But it's not enough for that cool, artsy long exopsure look. I have a shot I need that effect for, though, and have been thinking about how to get it. I think the best option would be a motion blur filter in post, after you have the shot up to your final speed.

November 25th, 2005, 11:51 AM	#8
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	You can't really get the same 'streaking headlight' effect with the VX/PD Brian. With a Super-8 film camera such as the Beaulieu you can expose each frame for 10 seconds, say, then immediately expose the next frame for 10 seconds and so on. On replay the headlights form one long stream on screen. With our video cameras you can dial down to 1/3rd sec per frame, but the effect looks quite different simply because the shutter isn't open for long enough. tom.