Home of Professional Cinematography since 1996

class="Paragraph" Slow - Mo Explosions In 24P

class="Paragraph" Published : 11th February 2004

class="Paragraph"
I have an upcoming shoot where we are "capturing a number of explosions in 24P", and that's all I've heard at the moment. I can't imagine shooting explosions without wanting to slomo the footage once they get to post, which leads to my questions.

I also have to assume that we're using the F900/3 by the way.

Please check my logic here, but I'm thinking that capturing as many frames as possible in the field can only be better for post, yes? I'm also thinking that capturing progressive must be better than capturing with interlace for footage that will inevitably be slowed down in post. But I can't help thinking that 59.94i will give me more information to work with later than 29.97PsF.

Has anyone done a test of slomo footage from the F900/3 at the available rates and found a preference?

I'm sure software and various post tools would make slow motion possible at any of the available rates in the camera, but is there a consensus as to what the "best" rate is to capture with for the post tools currently available today?

And I assume this would all be much easier with 60P from a Varicam, yes? But again, I don't think that's what I'll be using.

Thanks in advance for any advice!

Jay Farrington


class="Paragraph"
I've seen footage capture in 60i and turned into slo-mo with software at Lowry Digital and it looked terrific. His software takes information from multiple adjacent frames and with a few hundred Macs fills in the gaps - really impressive stuff. He's out in Burbank and a CML-lister.

class="Paragraph" Check it out.

Dale Launer
Writer / Filmmaker
Santa Monica


class="Paragraph"
Jay Farrington wrote :

>But I can't help thinking that 59.94i will give me more information to >work with later than 29.97PsF.

Yes, but at half the resolution, thus negating most of the usefulness of shooting in HD in the first place.

Sean Fairburn would likely disagree, but there is no free lunch. Using 60i and uprezzing the fields as an overcrank cheat is a dubious practice, and the results I've seen show it. If you can, I would ask for a film camera that day. That's what a number of HD projects have done, and it's still the only sensible way to achieve a quality result.

Just because you can do something doesn't mean you should.

Mike Most
VFX Supervisor
IATSE Local 600
Los Angeles


class="Paragraph"
Mike Most writes :

>Sean Fairburn would likely disagree, but there is no free lunch. Using >60i and uprezzing the fields as an overcrank cheat is a dubious >practice, and the results I've seen show it.

You'll get far better results shooting normally and then using ReTimer from www.realviz.com

Cheers

Geoff Boyle FBKS
Director of Photography
EU Based
www.cinematography.net


class="Paragraph"
I've seen footage capture in 60i and turned into slo-mo with software at Lowry Digital and it looked terrific. Dale Launer

Thanks Dale. And thanks for bringing in the footage you showed us at the workshop last month! It was great to see it!

Jay Farrington


class="Paragraph"
>You'll get far better results shooting normally and then using ReTimer >from www.realviz.com  Geoff Boyle

-Geoff, when you say "normal" do you mean 23.98PsF? Again, assuming I'm using the F900/3. Thanks.

Jay Farrington


class="Paragraph"
Jay Farrington wrote :

>I have an upcoming shoot where we are "capturing a number of >explosions in 24P", and that's all I've heard at the moment...

I cannot imagine you'll get very decent slo-mo image (or enough of it) when you're shooting an explosion at 24fps and then manufacturing the extra frames in post. Even the slowest explosions are done/finished in less than 2-3 frames. Less frames if you're framed tight on the
explosion.

I had a gig once where we needed to shoot slo-mo of some temple columns exploding (which would later be reversed and, using ReTimer, appear to re-materialize out of the air). I remember I tried to get Photosonics 2,500 fps cameras but we couldn't afford it, and we decided on the Mitchell that the VFX company owned.

Even at 120 fps the event was over in no time, and ReTimer was only able to slow the action down by perhaps an additional factor of 2-3 before you got artefacts. Its as if we shot at 240-360 fps. But if we had been able to get at least a Photosonics 4ER (360 fps) it would've appeared to have been shot at 700 to 1000fps.

Ever seen the footage shot of a dynamite stick exploding? At 10,000 fps drum-camera you can see it explode starting on the fuse-side and moving down to the other side of the stick. Now that's slo-mo.

Mark Doering-Powell
LA based DP


class="Paragraph"
If shot at 30p or 24p they could step-print it later. It's a definite look but it may work out okay. If the shot is wide enough it may not even need to be slowed down.

Most of the explosions I've shot have been on film at 120 fps, and that's mostly been primacord or squib hits. I don't know how you'd do that at 24p or 30p without using a fast shutter and step printing later. If the rest of the piece is shot at 24p then shooting the explosion at 30p would give you a -slight- edge... but you might need a microscope to see the difference.

Are you shooting something blowing up, or are you shooting an explosion?

If you're shooting something blowing up then you might want to see the parts flying through the air, and that's something an F900 at 24p or 30p will have trouble with. (So would the Varicam at 60p but you'd be in slightly better shape.) If the explosion is the star of the shot then hopefully the effects people will use something that puts out some smoke, or use something that burns slow and bright, like gasoline.

Art Adams, DP
Mountain View, California - "Silicon Valley"
http://www.artadams.net/


class="Paragraph"
>Ever seen the footage shot of a dynamite stick exploding? At 10,000 fps >drum-camera you can see it explode starting on the fuse-side and >moving down to the other side of the stick. Now that's slo-mo.

I have the photosonics demo/ bullet 10,000 frames Sears commercial-it's amazing.

Who did the dynamite one?

Photosonics are absolutely amazing. The 4ER movement removed looks like a barracuda in your hand!

John F. Babl
Miami


class="Paragraph"
>Geoff, when you say "normal" do you mean 23.98PsF? Again, assuming >I'm using the F900/3. Thanks.

I believe he means shooting at 23.98p or 24p or 29.97p or 30p (whichever you choose as appropriate for the rest of the piece) but NOT at 60i.

From what I've heard, the post people will be much happier creating intermediate frames from a series of progressively-scanned images than from a series of half-resolution interlace-scanned images.

Ultimately, I think the post house should be answering this question as they're the ones who are going to have to make it work.

Art Adams, DP
Mountain View, California - "Silicon Valley"


class="Paragraph"
Here's a question :

If Jay's footage was only displayed via NTSC, on tape or on DVD, wouldn't 60i do just fine for slow motion? After all, half of 1080 is 540 and is more lines than NTSC will deliver anyway.

Art Adams, DP
Mountain View, California - "Silicon Valley"


class="Paragraph"
Jay Farrington write :

>Geoff, when you say "normal" do you mean 23.98PsF? Again, assuming >I'm using the F900/3.

Whatever speed you're shooting the main part of the production at.

Cheers

Geoff Boyle FBKS
Director of Photography
EU Based
www.cinematography.net


class="Paragraph"
Mark Doering-Powell writes :

>I cannot imagine you'll get very decent slo-mo image (or enough of it) >when you're shooting an explosion at 24fps and then manufacturing the >extra frames in post.

There is a HD camera available that does 1,000 frames, Arri were showing a version of it at IBC.

My point really was that you'll get better results shooting at "normal" speed and using ReTimer than you will get messing with 60i.

Cheers

Geoff Boyle FBKS
Director of Photography
EU Based
www.cinematography.net


class="Paragraph"
My 2 cents ( from the bowels of Vfx)

Choice # 1 is a high speed camera

Choice # 2 all suck for an explosion

Retimer and all other morph based slo-mo have significant limits, yes I am sure Dale has seem a very good demo, but one demo shot does not make the shot YOU are doing possible, it just meant that the one shot they used for the demo is happy.....

There is often significant hand work, alot of roto to isolate area's that react differently to the morph engine, so any discussion of fast renders is negated by the inherently sllloooowwwwwww workflow, as a point of reference on a shot recently it took three artists a week to get the subject roto'd and the BG also roto'd into three sections, all retimed differently, a clean plate created out of surrounding frames (as there was a moving camera) and the whole mess comp'd together

Then it took twenty min to render on a dual proc workstation... after 150 hours of labour, a twenty min render is not a big deal, there is a place for big render farms, but this ain't it...

We used the new slo-mo morph engine from Speed Six in London, they are the phoenix rising from the ashes of 5D, it is the best of class IMHO, as was 5D's when it was avb - the S6 was in Beta, without a GUI (command lines only) but really did a good job on boundary area's,

I have had good results from Retimmer and the often overlooked BCC's "opticalflow" is also very good on the right day, it does backwards look-up for morph's, and the values are animatable frame by frame...kinda cool if you have loads and loads of time.

With retimmer I often have to reverse the shot as it will not look backwards for morph information, and cannot merge the information gained with forwards morph information, all allow you to jump frames and such like.... starts to give you an idea how time is sucked away
creating a really really good slo-mo

But I would not want to try to do an "explosion" with out some 3D help to create some debris flying, and 2D particles as well, as small & fast moving objects are the worst case for any retimming solution, and I have done these - it is a challenge indeed and yes the production would have saved enough to buy the producer a new Mercedes ( well a cheap new Mercedes A class) if they had shot it on film in the first place....the producer's Mercedes was pissed away by a lack of communication, not stupidity from the camera crew, no one but the producer and director knew that the shot was to be slowed.

I'm sure as he was signing the cheque that the lesson had sunk in <sigh> stupid producer tricks in play again and you can't base choices on a demo shot - all shots are different, and much more than the slo-mo engine is used to create a finished shot, it is only one of many softwares that touch the shot.

Talk to your Vfx supervisor as you can't run tests, but do look at shooting on high speed film as a cost saving measure.

As always your mileage may vary, good luck...

Dermot Shane
Visual Effects guy
Vancouver, Canada & Shanghai, China


class="Paragraph"
Geoff wrote :

>There is a HD camera available that does 1,000 frames, Arri were >showing a version of it at IBC.

This was the fx Cam from NAC: 1280x1024 or 1280x720 @ 100, 250, 500, 1000 fps

http://www.nacinc.com/

We will use a different unit from Ingo Kaske, forgot the product name...

Cheers

+++ Florian Rettich Medientechnik +++


class="Paragraph"
Jay Farrington wrote :

>I have an upcoming shoot where we are "capturing a number of >explosions in 24P", and that's all I've heard at the moment...

Seems like an oxymoron honestly. How do you really "capture" an explosion at only 24fps? They're VERY brief.

Roderick
Az. D.P. (has shot a few explosions)
www.restevens.com
www.12on12off.com


class="Paragraph"
Roderick E. Stevens wrote :

>Seems like an oxymoron honestly. How do you really "capture" an >explosion at only 24fps? They're VERY brief.

Its a digital world and nothing is very new after all is it?

Mark Smith
Oh Seven Films
143 Grand St
Jersey City, NJ 07302


class="Paragraph"
Jay

How much time and money do you have on this production with the explosions? Are you filming out for the big screen? Some of the new High Speed systems are very new and can be expensive to rent as well as a Photosonics system. But what is considered expensive to your production? Logistically can you jump between camera systems or formats on the day?

Contact Mike Condon at Clairmont Camera they have the NAK system for high speed digital work. They have a very impressive demo to show. This is a hard-drive capture based system. Mike can show you this system and give you real "hands on" advice.

I have played with and shot some test with the Time Extender system from Germany....It's very impressive as well and is available in LA through BandPro in Burbank. This is also a hard-drive capture based system.

I have shot with an F900 at 60i and de-interlaced back to 24P for slow motion work. It will sell for a quick commercial shot and some down-converted television show work....but I have not filmed out with this option. Most if not all HD Post Houses do this de-interlace gag. I have had good luck with CCI Digital and Victory Studios/Post solutions in the past. I have some slow motion needs on a network HD TV series I'm about to start shooting in Feb and this is the path I will probably take because of budget and time.

I also agree with Mr. Boyle about the Retimer post software. Ask your post house about this option while you’re on the case.

Remember....have fun at any frame rate.

Mike Spodnik SOC
DP Ashland, OR


class="Paragraph"
Jay Farrington wrote :

>I have an upcoming shoot where we are "capturing a number of >explosions in 24P"

Jay,

What is your final product? NTSC, 35 mm projection, or somewhere in between? For an NTSC final I have use the process of shooting 1080i and letting Victory Studios do a software conversion taking fields to frames.

It works great and clients are always very happy. I am not shooting explosions, however, and the slowest you can get is equivalent to 60 fps shot at 24 fps. I would discuss this with post houses and, as Sean would say, test...

Ian Ellis DP
Austin TX
600 op
f-900 owner
www.texashighdef.com


class="Paragraph"
Mike Most writes:

>But I can't help thinking that 59.94i will give me more information to >work with later than 29.97PsF.

Hi :

We have had considerable success with many scenes up-rezzing fields to frames for slow motion. The speed change is 2 1/2 to 1 if the end result is 24P.

The resolution is, in every shot that we have done so far, indistinguishable from the full frame resolution. It true that there is no free lunch...but there is lots of information, that we do not normally see, hiding in every motion picture sequence.

Powerful computer algorithms can do wonders.

Hence our success in restoration of old films and with blow-ups from 35mm and HD to the 15/70 Imax format. Dale Launer came in to our place in Burbank to see for himself.

I welcome any of you to do the same. Just give me a little notice.

All the best.

John Lowry
Lowry Digital Images
Burbank CA


class="Paragraph"
John Lowry wrote :

>We have had considerable success with many scenes up-rezzing fields >to frames for slow motion.

I don't necessarily disbelieve that. But the fact remains that 60fps is, in most cases, simply too slow a frame rate for shooting an explosion anyway.

The best and most correct answer for the question that was asked is and remains : shoot it on film.

Mike Most
VFX Supervisor
IATSE Local 600
Los Angeles


class="Paragraph"
As enthusiastic as I am about the slow-motion capability of the VariCam, even it's 60 fps progressive is not sufficient for an explosion. Until a high-quality high-speed video camera is generally available, film is the correct choice for this application.

Best regards to all,

Leo Ticheli
Director/Cinematographer
Birmingham/Atlanta


class="Paragraph"
>Using 60i and uprezzing the fields as an overcrank cheat is a dubious >practice, and the results I've seen show it. If you can, I would ask for a >film camera that day.

On "Joan of Arcadia", we have had a handful of instances thus far calling for slo-mo (usually between 60 and 96fps), and in each case have rented a film camera for the day.

Drew Matich


class="Paragraph"
>On "Joan of Arcadia", we have had a handful of instances thus far calling >for slo-mo (usually between 60 and 96fps), and in each case have >rented a film camera for the day.

It's also what we (well, Mark Doering Powell and myself) did on "Family Affair."

And Hi, Drew. Didn't know you were here. Hope things are going well - "Joan" is a hit (rare these days), which is always good, but I would also think it's an interesting gig for you, being an HD drama (also rare).

Mike Most
VFX Supervisor
IATSE Local 600
Los Angeles


class="Paragraph"
Jay,

I just saw some high speed footage done with the NAC fx cam. The final image quality was HD video, let's say some how close to what I have seen from Hi Speed film cameras on to HD format, although cleaner due to no grain, but of limited dynamic range, a slight strobe and non organic. Frame rates 100, 250, 500, 1000. Pixels 1280 x 1024.

Resizing to 1920 x 1080. The shutter speed corresponding to frame rates and up to 1 / 2000,000 s.

It would definitely do the job for what you're looking for.

Germano Saracco D.P.
www.germanosaracco.com


class="Paragraph"
>And Hi, Drew. Didn't know you were here. Hope things are going well - = >"Joan" is a hit (rare these days), which is always good, but I would = also >think it's an interesting gig for you, being an HD drama (also = rare).

Hi back, Mike. I just lurk usually...someone brought the board to my attention after "Dawson's Creek" got some cinematographic (is that a word?) props a couple years back.

"Joan" has been a great experience so far...a ton of hard work after two years on "Dawson's", but very stimulating and usually a lot of fun. I hope we can keep the viewership, but everyone seems satisfied so far.

It's the first time originating on HD for just about everyone on the show, including Charlie Lieberman, our DP, who came to us from "Everwood". He did a ton of
homework before production started, and it shows, I think.

Drew Matich


class="Paragraph"
Mike Spodnik SOC writes :

>Clairmont Camera...NAC system for high speed digital...F900 at 60i and >de-interlaced back to 24P for slow motion...Retimer post software...

Mike,

Thanks for all the info. Turns out this will be a controlled test, explosions only (no objects blowing up). We may try a number of different solutions, but all within the digital realm. Not for film out. Relatively low budget, but this section of the footage might get more resources than the other things we're shooting for this project.

And thanks much to everyone for all the off-list emails! There's a wealth of information there that we will put to good use.

Thanks again!

Jay Farrington HD DIT