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ramping in post - bad idea?


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#1 claudio rietti

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Posted 18 October 2005 - 11:09 AM

hi. i'm shooting a spec commercial to enter into a student competition and the director wants to ramp. We are shooting on super 16 and the ARRI SR III is too expensive to hire. We can get a great camera (Aaton XTR) for free, but it does not have ramping capabilities, or the ARRI SR II for really cheap. I prefer the Aaton, personally, but that's beside the point. If we were to gradually slow down or speed up the image in post it wouldn't look quite the same, but would it be passable? Are there any other super 16mm cameras that has ramping capabilities that i might be able to get for cheaper? Does anyone know any camera houses in london that might have better deals for students on the SR III? The ones i have called have quoted me ridiculous prices (for what we can afford), but i will keep calling back hoping to speak to someone in the right mood at the right time of day.

thanks for the help,
Claudio
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#2 Matt Sandstrom

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Posted 18 October 2005 - 11:48 AM

if you shoot the entire scene in the highest speed you need so that everything is in slow motion and speed up the normal parts in post it will look pretty much exactly the same as an in camera ramp, since the camera changes shutter angle to maintain exposure, but it will waste a lot of film.

/matt
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#3 Michael Collier

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Posted 18 October 2005 - 03:43 PM

if you shoot the entire scene in the highest speed


Good advice. That will put just the slightest amount of stutter to the image as a result of dropping frames and blending other frames together during the ramp, but those artifacts wont be noticable. Get a good software package to do this on. AfterEffects has time remap, a tool I use a lot to get similar effects. I once did a music video where it was slow motion until a drum beat then the speed would up until the actor placed the next foot down, so as to time his walking to the music. I emphasized the speed up and slow down to get a more stylized finnish

If you do end up shooting at a high framerate, dont feel confined to just a linear ramp. you can get really cool effects if you play around with it.
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#4 claudio rietti

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Posted 19 October 2005 - 02:35 AM

thanks for the advice, but one of the stifling limitations is that we are limited to 400' of film, so stock is an issue. this is not a matter of budget, it's the rule of the competition which will be monitored closely. We'll have to work something else out, me thinks.
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#5 Phil Rhodes

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Posted 19 October 2005 - 06:53 AM

Hi,

Well, I think you're asking for trouble, then - you're limiting yourself to video-style work with software like Twixtor. This can work very well - one trick is to shoot a small shutter angle, so it doesn't end up just tweening blur.

Phil
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#6 Daniel J. Ashley-Smith

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Posted 19 October 2005 - 07:27 AM

Just wondering, what is "ramping"?

Tnx,

Dan.
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#7 Riku Naskali

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Posted 19 October 2005 - 08:13 AM

I have a question concerning ramping, too. I'm considering ramping without compensating for light loss since I don't have any means to do it except manually. And that doesn't feel accurate enough.

One stop should be easily correctable in telecine given my scene fits nicely in film's range, right?

I thought of overexposing one stop and thus ending the ramp on "correct" exposure, does this sound ok?
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#8 Dickson Sorensen

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Posted 19 October 2005 - 08:19 AM

Just wondering, what is "ramping"?

Tnx,

Dan.

"Ramping" is a term that describes that change of frame rate during a shot. You can ramp from under cranked up or the other way around high speed down. The query doesen't say what direction they want to move in. The trick with ramping is to change the lens iris or shutter angle at the same time as the camera changes speed keeping the exposure the same. One could do this manually by carefully making marks on the f stop ring and you change the tach move the f stop. Example: 36fps to 18fps.- f stop 5.6 at 36 fps.- as you drop the speed to 18fps (increase exposure one stop) you will need to change to f8 (decrease exposure one stop) to compensate. You don't need a high tech camera to do it manually. Practice without film in the camera if you have a limited amount of film.
Some modern cameras automate this with computers and servo motors.
One of the drawbacks of doing this in camera is that there are limitations as to how fast you can make these changes due to the mechanical momentum of the camera. You are also limited to the cameras speeds and the range of your fstop or variable shutter. In post you have a lot more latitude and can change speed instantly.

Edited by Dickson Sorensen, 19 October 2005 - 08:27 AM.

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#9 Andy Sparaco SOC

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Posted 19 October 2005 - 08:21 AM

The opposite approach is to shoot normal speed and slow down portions in the Xfer. The strategy is xfer normal speed then xfer select shots at 6fps or what ever and edit them together. Usually the colorist will do a short additional layoff at a "metaspeed" after the primary xfer

Shoot at 6 fps and xfer at 6fps you get slow mo without burning a lot of film also. Use this approach a lot the effect is not a "smooth" slow mo more of a "stepping feel"

Also have done 6 and 8 fps Sync sound another interesting effect

Shooting at 30/32/36/42/ 48 or faster and Xfer at the same film rate speed also has an interesting effect. sometimes use this approach when the client wants an "HD" look.

Manipulating camera and xfer speed in combination is an often overlooked technique
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#10 Dickson Sorensen

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Posted 19 October 2005 - 08:23 AM

I have a question concerning ramping, too. I'm considering ramping without compensating for light loss since I don't have any means to do it except manually. And that doesn't feel accurate enough.

One stop should be easily correctable in telecine given my scene fits nicely in film's range, right?

I thought of overexposing one stop and thus ending the ramp on "correct" exposure, does this sound ok?


If you are only changing one stop and rehearse the change you will be suprised how accurate it will be. Have an assistant help you make the change and do an extra take or two if you can. I have done it manually and low and behold it was fine.

Edited by Dickson Sorensen, 19 October 2005 - 08:27 AM.

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#11 Andy Sparaco SOC

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Posted 19 October 2005 - 08:31 AM

in a similar vein you can punch the framerate button on your speedcontrol up in units of 10 like 24fps to 34fps and let the colorist equalise the 1/3 of a stop or so of under exposure in xfer.

A "poormans ramp"

Repair folks say you can fry the electronics on a camera motor, so be fore warned.
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#12 John Pytlak RIP

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Posted 19 October 2005 - 09:25 AM

in a similar vein you can punch the framerate button on your speedcontrol up in units of 10 like 24fps to 34fps and let the colorist equalise the 1/3 of a stop or so of under exposure in xfer.

A "poormans ramp"


Can work somewhat for a small change in speed, but as the exposure change approaches a full stop (2X speed), the underexposure may start to produce a noticeable change in tone scale. For color negative film, best to start off with a bit of overexposure, so the ramp up in speed keeps the scene content on the straight line portion of the film's curve shape.

Also, on film printers, you are limited in how many frames are required to make light changes. A full stop of camera exposure requires about 7 printer lights change, spread over the length of the ramp. The ramp may contain slight "jumps" in density as the printer light changes.
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#13 Benji Wade

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Posted 19 October 2005 - 10:09 AM

If you shoot with relatively high speed film, I don't see why AfterEffects wouldn't produce a decent result?
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#14 Benji Wade

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Posted 19 October 2005 - 10:25 AM

Here's a music video from a UK hip-hop band called Virus Syndicate. I believe this was all done in post:

http://www.planet-mu...own_mov.torrent

That video was retimed with Twixtor 4.5, and I think it was done with XL2 footage.
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#15 matthew david burton

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Posted 31 October 2005 - 09:02 AM

Here's a music video from a UK hip-hop band called Virus Syndicate. I believe this was all done in post:

http://www.planet-mu...own_mov.torrent

That video was retimed with Twixtor 4.5, and I think it was done with XL2 footage.


Hello forum
I was responsible for creating the virus syndicate video "Slow down" for planet-mu records.
Yes it was done in post using re:vision effects twixtor 4.5 inside after effects ( yes the plugin will work under fcp or avid however ae is the only app that it works well with).
If used correctly twixtor can give better results than simple camera ramping alone. The best way to use twixtor would be to use it in conjunction with ramped source footage but this is never an option for low/medium budgets.

I have a web friendly version of the "slow down" video if anybody can help me host it ?

cheers
-matt :D

Edited by matthew david burton, 31 October 2005 - 09:04 AM.

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#16 Matt Sandstrom

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Posted 31 October 2005 - 10:39 AM

seems like nobody's seeding that torrent...

/matt
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#17 matthew david burton

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Posted 16 March 2006 - 06:19 PM

seems like nobody's seeding that torrent...

/matt


Try this link for video Click to play
Thanks Jason for hosting file over at steadiforum :D
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#18 James Steven Beverly

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Posted 16 March 2006 - 10:06 PM

It seems like an mos camera w/ a reostate motor would be perfect for this. I have a Konvas 1m w/ a reostate motor. It's not an expensive camera and should be very cheap to rent (not mine of course but in general). If there's no dialog in the scene. It should work Even if there is cutting to a different angle and cntinung the scene at that point would also work.
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