Home of Professional Cinematography since 1996

Film Speed Ramps...Basics

>Y'know those groovy "ramp shots", where the camera is cruising along slowly on a dolly, then zips into say a close up of a subject at warp speed then resumes dollying at a slow speed - all without cuts or seemingly affecting the speed of the live action subject.

>I know how to do that shot motion control but I've seen it used on $1.98 local music videos. How is this done on the cheap?

>Does anyone have any good low budget, high impact speed ramping or "time bending" type tricks they can share? I'm doing a commercial with this theme and don't have a large budget for effects. Ideally tips for shots that seemingly affect the central caracters surroundings while leaving them in "current time / space".

>Thank in advance -

>Byron Pickett


>There is a similar effect which can be done in post. My recollection is that you shoot the entire setup at the highest camera speed for the slo-mo and then the post FX creates the fast motion. Wether that is cheaper in post than live, I have no idea.

>Jim Sofranko NY/DP


>Editing a music video right now and doing the psuedo ramping in post. first of all, I've attempted this before, but Idid not shoot the original footage in slo-mo and the fake ramping looked fake and stuttery - even using frame blending (after effects).

>Now I try to shoot at least 48fps and Ifind faking the ramping via keyframes in AE or even simply cutting up a single clip into segments and individually altering the speed/duration, seems to do the job reasonably well. You really need those extra frames to make the transitions smooth. The whole effect looks rough if you have to slow down (duplicate) frames in the computer. I'm sure there are several other better ways to do achieve this and other, more computer/editor types, might share their low budget techniques.

>Cheers,

Dave Luxton

Edmonton, AB


>I thought it was done by shooting it normal or high speed, then losing selected frames in IP. Step over one frame a few times, then two, then three and so on, reversing the process to resume the speed. Did that way back on one of my epics, learned it from one of Norman McLaren's films (Neighbours). That seems to be the cheapest way to do it. Works fine.

Robert Rouveroy csc

The Hague, Holland


>You can do this in-camera, or in post production.

>When using ARRI cameras, you can do this effect in-camera with the 535, 535B, 435, 16SR3, 35-2, BL and 16SR1/2. 535 and 435 can compensate for exposure change with the electronic mirror shutter, all cameras can use the Iris Control Unit (ICU) to compensate with the iris. It is now also possible, using the WRC-1 Wireless Remote Control, to combine shutter, iris and fps ramps, for a variety of cool effects (how about JUST ramping shutter and iris to change depth of field?).

>Carefully check into the cost of doing this in post (which can be substantial if you want it to look good) versus renting one of the above cameras.

>If you go post, you can either shoot at high speed, and then do the ramp in post (uses more film stock on the set, but will end up looking better), or shoot at normal speed and have some specialized piece of software interpolate a bunch of new images (uses less film stock, but can be very expensive). I just saw some software that does this at SIGGRAPH, and it is still a very cumbersome process.

For a short and concise (= many pictures, little text; I learn from my children these days about user interface design...) tutorial on in-camera ramps, send me an email and I can send you the PDF "Ramp Tutorial" I just finished (not on the ARRI website yet) as part of my Ramp Preview Controller project.

>Also, feel free to call me with any questions on in-camera ramps.

>Regards,

Marc Shipman-Mueller,

Technical Representative

Arriflex Corporation

1646 North Oakley Ave, Suite #2, Chicago, IL

60647-5319, USA

http://www.arri.com


>Dear List,

>Thanks so much for all your generous responses.

>Here is a very condensed = summary of what I learned.

>Shooting vs post: If a high frame rate is used (highest FPS one needs fo= r the slo-mo portions of shot) one can avoid interpolation and frame duplication and greatly increase the likelyhood of acieving a clean and jitter free ramp in post. Obviously if one can get the shot in the fiel= d without an undue number of takes (and assuming the staging is easily repeatable) then you've saved money in post and maintained control in camera (who knows who'll be cutting it, right?).

>This obviously needs to = be judged on shot to shot basis.

>Content & Staging Matters. Big time. Is it motivated by story and movement in the frame?

>Are you designing moves and scenic / set pieces = that will compound the effect?

>Layers of depth in staging seem to help a = dd to the effect.

>Thanks all !

>Byron C. Pickett


>Can I add a couple of points to Byron's summary, from a post-production point-of-view? - and I hope I'm not repeating anything - I've just joined the list, so forgive me...

>There are a few pieces of software available in post now, that allow one to "slow down" shots to make, for example, something shot at 24fps look like 1000 fps, and so on. This is not achieved as previously by doing a "rolling mix" between photographed frames (often yielding a steppy, jittering look), but instead by the software analysing the motion of edges within the sequence ("image flow"), and then creating the new frames needed with a kind of morph of the nearest actual frames.

>This can produce astounding clean and realistic slow motion effects (even rocking and rolling back and forth, slowing to a halt, etc), though sometimes image artefacts need to be cleaned up (particularly around the edges of frame, and around occluded/revealed material). Using the same technology, one can also speed up shots, though obviously this is less demanding, as having more frames than you need is preferable to having to create new interpolated frames.

>Finally, one can adjust the amount of motion blur on shots (effectively controlling the shutter angle in post); certainly you can create more motion blur - I'm not sure if you can make less - I think not, but I've never tried.

>Software packages that incorporate this stuff include Kodak's Cineon (the first package to have it, called the process "Cinespeed"), RealViz and most recently, discreet Inferno.

>As a real-world example of the usefulness of Cinespeed, for a recent Guinness commercial (the one with the surfers and the white horses) we had lots of background plates of surfers in Hawaii, shot at a whole range of frame rates, from 24fps up to over 200. Then, in the studio, we had to shoot a whole "library" of leaping horses at various angles against blue to then comp into the waves. Rather than have to shoot all the horses at a range of frame rates too, we opted to shoot all the horses on 2 Photosonics cameras running at (as I remember) about 250 fps, and then Cinespeed the horses to match the frame rate of each particular background plate, on demand. This worked beautifully.

>hope this is of interest to someone

Paddy Eason

Computer Film Company, London

http://www.cfc.co.uk


>I did some research, and found the following: You use the Iris Control Unit (ICU) for exposure compensation with the 535, 535B, 435, 16SR3, 35-3, 16SR1, 16SR2 and 765, but not with the BL. Something about the BL electronics just does not mesh with the ICU.

>Now, if you want to use the ICU with one of the older cameras, you need to vary the speed with the Variable Speed (VS) box, or, on the 35-3, you can simply diddle with the small speed wheel on the camera. Be careful, though: neither method is crystal speed, and neither one is very precise. For more precision you should use the Preston Speed/Aperture unit.

>With the new cameras (535, 535B, 435, 16SR3) you can use a variety of cool crystal precision controllers: - Remote Control Unit (RCU) - Wireless Remote Control Unit (WRC) - Laptop Camera Controller (LCC) - Ramp Preview Controller (RPC) - Camera Control Unit (CCU)

>Here is a list of what cable you need to plug in (and where) to use the ICU with the different cameras:

>535, 535B: LC-D1 to RU receptacle SR-3, SR-3 HS, 435ES: LC-D1 to ACC receptacle 35-3, 435, 435ES: LC-D2 to 11 pin receptacle SR-1, SR-2, SR-2 HS: LC-D4 to 11 pin receptacle 765: LC-D3 to SCU receptacle

>We also have cables available for Aaton cameras.

>Regards,

Marc Shipman-Mueller,

Technical Representative

Arriflex Corporation


>You are correct that physical film cameras cannot change their speed as fast as you can in post production. If a fast snap ramp is called for, post is all you can do. But post production has its own problems (expensive, time consuming, possible artifacts), and, as someone else already pointed out, a ramp that is physically impossible looses some of its organic quality, it looks impossible, and thus artificial.

>Regards,

>Marc Shipman-Mueller


>The only exception might be when you ramp from, say 24 fps to 5 fps (or vice versa).

>RCU will tell you fastest time is 0.7, and so we triple that (to be extra cautious) to ramp in 2.1 sec, which supposedly gives you about 1.2 sec screen time (I don't have the RCU in front of me, but I believe these are the values).

>However, upon playback the linear ramp will feel a lot quicker and "slam" near the lower speed. It feels more like 0.3 sec screen time. Pretty instant. I've tried that ramp at 1.5 sec and it was absurdly fast, no ramp to speak of.

>Too bad the RCU doesn't let you round the ramps on the lower speed. Need a laptop for that. ...and I still wish the RCU/ICU let you do iris-only tweaks for day/ext with the handwheel.

>Mark


>We do not have an official list, but here is what I personally know about:

>1. ARRI Wireless Lens Control System (WLCS) There are cables to power the WLCS from Aaton cameras, and to use the camera RUN function.

>2. Iris Control Unit It is possible to run the ICU on an Aaton camera with the proper interface cable.

>3. Matte Boxes

>4. Follow Focus

>5. Lenses Most Aatons have or can be equipped with PL mounts that will then accept any (JP, any restrictions there?) PL mount lenses. That includes speciality items like the Shift & Tilt System, the Tilt Focus lenses, the Macro lenses, etc.

>6. ARRIHEAD Of course you can mount ANY camera to that (I have even heard rumblings of a 24P HD camera on an ARRIHEAD recently,...).

>That is all I can come up with. Anyone else on the list have anything to ad?

>Regards,

>Marc Shipman-Mueller


>Yeah, but it seems that something called the IRIS CONTROL UNIT would also have this feature allowing one to, how shall I put it, control only the iris with that simple (less pricey) RCU/ICU setup.

>What is that? one more click position on the settings wheel called "iris only w/ handwheel" and update the software inside ? I certainly make it sound easy. Arri drafting me a letter now saying, "fine, so you do it !".

>Yes, the "slam" is a function of linear ramp, and the option to soften the ramp or the lower fps via RCU would probably take more fiddling (and yet another button). And Arri wants us to buy/rent the LCC or WRC...

>Still, I use the RCU/ICU all the time due to its speed and simplicity and because we cannot afford anything else. The steadicam guys hate me, but I can point them towards budget/production.

>Mark Doering-Powell


>True, and a good idea, but technically very difficult to implement. If I may get technical for a moment: The RCU communicates with the camera via a serial digital data stream (RS-232). The ICU, in contrast, communicates with the camera via an analog signal. The ICU receives the shutter pulse from the camera and measures this pulse. If the frequency of the shutter pulse changes, the ICU will change the iris ring accordingly. So, when using RCU/ICU, the RCU has no idea that the ICU is connected. The RCU simply changes the speed (fps) of the camera, completely ignorant of the ICU's presence or absence. The ICU on the other hand does not really care about the RCU, either. As long as the fps changes, it receives a shutter pulse and change the iris. How the fps is changed, the ICU does not care nor know. RCU and ICU not only talk different languages (RCU: digital, ICU: analog), but they also never talk directly to each other.

>Mark Doering Powell wrote :

>Still, I use the RCU/ICU all the time due to its speed and simplicity and because we >cannot afford anything else. The steadicam guys hate me, but I can point them >towards budget/production.

>Well, I hate to repeat myself, but the Steadicam guys will LOVE the Wireless Remote Controller (WRC). They will loose the cable (and then love you, is that not worth anything?), and you will be able to twiddle the iris anytime from anyplace to your hearts content.

>Please, someone stop me before Geoff does,...

>Regards,

>Marc Shipman-Mueller


>I will ask my producer how much our Steadicam Op's love for me is worth to him. I expect he'll answer that hateful Steadicam has worked in past so why should he pay for love.

>Realities of production. Plus, I don't think our rental house has WRC yet, but I'll look into it.

>but what if RCU had an analog output that "fooled" ICU into different fps pulses (via RCU handwheel) to tweak iris on partly cloudy day/ext or shots that go day/ext to dark cavernous interior.

>I know, I know, get the WRC...

>Mark