1000 fps Phantom Flex shoot - Part 4 - Resources


RESOURCES:

In addition to the help I had from Chris Chomyn and the crew, I also did some homework preparing for my first 1000fps Phantom Flex shoot.  Here's some online resources where I found useful information:

Phantom Camera Info





Lighting for high-speed:



1000 fps Phantom shoot - Part 3 - Camera Notes


While I've done a fair amount of food work and shot 300 fps with an Epic before, I'd never tried 1000 fps and never used a Phantom.  That meant lots of research and preparation.

The brief from the director called for falling food and splashing water with camera employing a long macro lens and moving fast on a skater dolly.  

In my experience as a first-time user, the Phantom Flex camera was dead easy to understand and use.  The only oddity was that the frame rate was called "sample rate" - a nod to Vision Research camera's other users in the scientific research and manufacturing fields.  Pretty cool if you ask me.  My dad is a physicist and yes, really, rocket scientist.  We think he's used data from Vision Research cameras before.

At any rate, I was also fortunate to have a great DIT from RSVP rentals in the Phillippines who handled all the technical aspects and even triggered the roll for me.

Say you can't count on being lucky like me. Here's what I learned about using the Phantom camera:

BLACK REFERENCE

So you've done the lighting right and have plenty of it, the big gotcha! that could show up in post but might not be apparent on set, is bad black balance.  At 1000 fps and up, the camera sensor gets very hot, very fast.  Consequently, the sensor can't hold the black point.  That can make the footage wonky in the shadows when you go to color-grade.  On-set playback is reasonably reliable, but I don't like to take chances if I don't have to.

If you're using an Phantom HD, black balance is more of a concern than with the Phantom Flex which has a proprietary HQ mode, which as I understand it, uses something like HDR to help correct for black balance issues.  Nonetheless, it's a best practice to run "Black Reference" before each take.  At 8s to run the routine, it's not such a big deal if you keep that in mind before each take.  

In my research, it seemed there were three different methods of doing this, with the suggestion being to pick one and be consistent.  In practice it was much simpler: let the DIT push a button and wait a couple seconds while the monitor displays black.  On the Phantom Flex there's a dedicated button for black reference, so it's pretty easy... on a food shoot.  A mountain-bike competition might require some anticipation.

RAM RECORDING

The other trick to the Phantom is triggering the recording.  In basic record mode, the camera records a continuous loop to camera RAM.  This is due to the enormous amounts of data being processed.  There is no commercially available non-volatile storage medium that can handle that kind of data throughput.  RAM recording is very cool because you can trigger recording after an event has happened. But it does have some downsides.

The big potential gotcha! with looped RAM recording is that a take exists only in camera RAM until you dump it to non-volatile storage.  

With a Phantom, whatever you capture to RAM can be dumped to a CineMag or an external recorder.  If you can afford the CineMag rental, get a couple.  It's simple, fast & makes your shoot easier.  Transfers are blazing fast, but the CineMag records data sequentially, so if you save every frame of every take, you'll fill up fast and you'll have to transfer data before you can format the drive.  It takes a goodly chunk of time to transfer the data to your HDD RAID array.  It takes a lot more time to play the take back in real-time to an external  recorder

Brilliantly, you can save to CineMag only the takes you like and only the portions thereof which you intend to use.  In other words, think of circled takes as you would when shooting 35mm film; transfer only those and the CineMag will serve you well.

If you go back into record-mode without transferring the data in camera RAM, that amazing unreproducible take will be gone forever.  The camera guards you against this, but 18 hours into the day... well... try to be careful.  

If the camera loses power before you dump the RAM data, it's gone.  If you're using batteries, this can easily come up to bite you.  The Phantom is a juice-hungry beast so batteries go quick, especially with the heat of all those lights in the studio. If the battery dies before you dump your data, you're once-in-a-lifetime take is lost forever.  A/C power is a better choice if you're in a studio.  Just watch those cables.  Power outages are a pretty common occurrence in VN.  Khanh at HK Film dug me up a UPS for the camera's A/C power supply.  Yes, I'm that paranoid.

RECORD TRIGGERING

The unusual aspect of looped RAM recording is this:  you're loop is limited to the amount of RAM in the camera.  Depending on your frame rate and quality settings, you're looking at 3-10 seconds of record time.  It's a good idea to practice triggering.  

On a Phantom you can set the trigger to any time within the limits of the RAM buffer. For my practice, I had Jeremy set the trigger at about 2/3 of the available record time.  With the 10s of record time I had available, I could trigger the record when I saw what I wanted and have the 6s before and 3s after, accounting for the lag between my eyes and my muscle twitch.  

You don't need a $100,000 camera to practice this. Watching a high-speed event and snapping will work just fine.  And here the Phantom is much easier than using film because you don't have to take into account the time it takes a film camera to get up to speed and try to synchronize that with the event you're trying to capture.  For picture, I had Jeremy trigger, since he was more experienced.  I always love having crew who know more about their job than I do.

ET CETERA

There's a PC software interface for the Phantom camera.  Vision Research offers it as a free download and it will operate with a simulated camera just in case you don't have an extra Phantom or two laying around the office.  Unfortunately the software is Windows-only.  Vision Research offers some decent, if tedious, software tutorial videos as well. 

Other than RAM-recording and record-triggering, the Phantom works like any other professional CMOS sensor, Bayer-pattern digital cinema camera I know of.  You've got RAW recording to disk.  You're monitor will show applied metadata (ISO, Color Temp., etc).  You can run HD-SDI to an external recorder.  Camera settings are clear and easy to adjust.  You've got exposure-check in the viewfinder and the Vision Research software will give you a histogram.

Basically the Phantom camera was reliable and pretty easy to use.

1000 fps Phantom shoot - Part 2 - Lighting


While I've done a fair amount of food work and shot 300 fps with an Epic before, I'd never tried 1000 fps and never used a Phantom.  That meant lots of research and preparation.

The brief from the director called for falling food and splashing water with camera employing a long macro lens and moving fast on a skater dolly.  I figured I'd need enough light to shoot at an aperture of at least f/4, but for preference f/8.  

For lighting I had 2 basic concerns: having enough light and making sure it didn't flicker.

At high frame rates, most lights powered be normal alternating current power will tend flicker.  The rule of thumb is that when you go above 120 fps with 60Hz power and 100 fps with 50Hz power you can expect flicker.  

And I thought I'd never use math after high school.

The simple way to avoid flicker at high frame rates is to light with the sun or use DC power.  On this shoot neither was an option.  In that case, it's a good idea to have a waveform monitor or vectorscope on set to check for flicker.  Also not an option for me.

Okay.  What now?  Play it safe I guess.  Time for some research.

CHOOSING LIGHTS

First off, my mentor Chris Chomyn suggested looking into strobe lighting from Unilux or Claremont and possibly augmenting it with big tungsten lights.  

The strobes give a super cool crispness to the image.  Possibly too crisp. So you can proportionally add some big tungsten to fill it out and have a little motion blur.  Chris pointed out that the big upside to strobes is that they operate a significantly lower temperatures.  This is a very big deal when you're shooting food or actors.  Downsides to strobes: not domestically available in Vietnam,  high rental cost, and needing a to sync your light meter and camera with the strobes.  No strobes for this job.

HMI's:  I usually use HMI's in Vietnam due to the superior power efficiency and having a bit more juice in the blue channel.  At high frame rates, HMI's can tend to flicker.  As an added bonus headache, you can get phase shift from the bulbs, where, as I understand it, the brightest point on the filament moves right and left, causing some weird directional and color shifts.  Arri and others make high speed ballasts that correct this, but like most specialized equipment, I'm not expecting to find it in Vietnam on a normal budget.

In my research online, I read that even without a special ballast, big HMI Fresnels might be okay but PAR's will probably flicker.  The suggestion was to test each individual light you intend to use - sometimes changing the ballast or the head can add or remove flicker.  Without a camera test, I decided not to chance it.  In the past I've had no trouble with 300 fps, 50Hz and off-brand 2.5k HMI Fresnels. But still...  No HMI's for this job.

LED's:  Reportedly, LED's don't flicker if you don't dim them.  f/8 at 1000fps with LED's... I've heard of the lights that can do that, but I haven't seen them.   In any case, definitely not available for this job.  So, no LED's.

Kino's:  Reportedly, Kino ballasts cycle power so fast that they shouldn't flicker up to several thousand fps.  My experience leads me to believe otherwise, even if it was most likely a maintenance issue or I had Chinese knockoffs and in the heat of the moment I didn't notice the substitution.  In retrospect, a 4' 4-bulb Kino 4-select System would have been quite useful, but I wasn't taking any chances. A 4'x2' bounce did the trick instead.  I would have given a good Kino system a try untested, because on two shots, if it worked it would have made that little difference only a professional will actually see, but any viewer will feel.

Excluding even more exotic options, I choose Tungsten lights.  Cheap and available.  Excellent.

AVOIDING FLICKER

In terms of having enough light, again shooting in the sun is the safest way to go.  Since I was shooting inside, I figured I couldn't possibly have too much light while I could easily have too little, so I basically ordered as many big tungsten lights as I could get within the constraints of budget and availability.

Tungsten, A/C power and high speed; here's the conventional wisdom:

The bigger the light the less chance of flicker.  For reasons not fully explained, but seeming to do with the size and cooling rate of a tungsten filament, at 60 Hz, 2k and above is considered safe.  For my job using 50 Hz power, lights 5k and above are expected not to to flicker.

Of course, I found that one website from some high speed specialist company which said the safe minimums were 5k/60Hz and 10k/50Hz.  Lights of that size are in short supply here.  Maxi-brutes aren't much use since it's actually nine 1k globes which pretty much guarantees a flicker.  Fortunately, there are a couple things that you can do with smaller Tungsten lights to help mitigate flicker.

Firstly, you can set the camera to a more open shutter angle. On a Phantom, I believe the max is 359°.   Regardless, I went with a 180° shutter because that's what Chris suggested for a nice balance between sharpness and motion-blur and on the day it looked great.

Secondly, you can put your lights on separate power distribution phases.  I was working with typical 3-phase 220V/50Hz power, so for every light under 10k I ordered sets of 3 and asked my best boy electric, Cuong, to wire one of each to the A, B, & C phase.  For top-light I used three 6x1kW space lights.  For each space light, Cuong rewired the lights so that two 1K globes were on each phase.  I pushed all three space lights through a 12'x12' gridcloth and there was no flicker as far as we could tell on the histogram or in playback.  Due to the heat from the floor lights, we set frame and rehearsed with just the space lights. As far as I could discern on set, separating the phases and pushing them through the diff worked a treat.

My six 5k's were similarly wired to separate phases and displayed no apparent flicker.  I only had two 10k's, and they were fine too.

SETUP

As one might expect, 68,000 watts of tungsten lighting at a distance of 3m and less generates an uncomfortable amount of heat.  Even with a frame of diffusion softening every light, our lettuce lasted only three or four 10s takes before it wilted.

Here's a photo of the lighting setup.


Here's a general rundown of my lighting design: the light from right side is brighter, slightly harder and somewhat higher up while the light from the left is softer and lower.

I arranged the space lights on top in a reverse pattern from the floor lights to soften shadows.  The space lights also gave enough light to let us turn off the floor lights while setting the frame and rehearsing. That let us do at least some of our work without feeling like we were inside an oven.

WRAP-UP

Other notes of interest on lighting for high-speed food photography:

1. Wrapping yourself in a light-colored towel is helpful if you find yourself standing directly in 68,000 Watts of tungsten lighting for any amount of time.  Yes,  I'm still finding new uses for the venerable Khăn hôi.

2. Say you've got food that needs to fall though frame in a fairly even arrangement and the props people had planned to drop it by hand, but that just isn't working out.  It just so happens that a 5k shutter makes for a passable mechanical drop apparatus in a pinch.  It worked out for me on this job, anyway.

3. Finally, some of the most helpful advice Chris Chomyn gave me for this job:

"Don't let your need for lots of light overshadow the quality of your lighting....remember the math and light for the desired visual effect....just use more of it in proper proportion from the right angles for your slo mo...."

That's really the key to lighting for high-speed.

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UPDATE:  The results.

My first 1000 fps Phantom Flex shoot - Part 1

Background

A couple weeks ago I got a call from a commercials producer I quite like working with who asked if I had ever worked with a Phantom camera.  I had not.  I added that I would very much like an opportunity to do so.  And I got it.  1000 fps here I come, ready or not.

In Vietnam, Phantom cameras are not available domestically.  For this job, we booked a camera from the Philippines for the day of the shoot. Now, I'll try pretty much anything once; if I don't have experience with some technical aspect of the job I figure that's nothing a camera test or two won't fix. Except, since the camera gear was coming from the Phillippines at significant expense, I would have no opportunity to familiarize myself with the camera and do testing.

So I did the next best thing and asked my mentor Chris Chomyn for advice.  As usual, he gave me plenty of useful information and it was a great starting point for my prep.

As things turned out, I was fortunate in two respects.  First, my camera was the Phantom Flex, not the Phantom HD Gold - the 1000 ISO sensor sensitivity and HQ mode make life much easier.  Secondly, RSVP rentals in the Philippines provided a great DIT who handled all the camera settings, record triggering and playback.  Jeremy insulated me from all of that and I was able to focus on getting the image.  He even helped my local crew learn how to use the P+S Technik Skater-Mini dolly for the first time.

I also want to acknowledge Nguyen Tuan Khanh at HK Film, who went to a lot of trouble to find us a P+S Technik Skater-Mini dolly for the shoot, and then took a big glass door off of his office when we found we needed a smoother surface than what the art department had provided.

Most of what I have to say about working with the Phantom at 1000 fps is technical or practical.  Aesthetically, well pretty much anything you can see moving is going to look mesmerizing and beautiful.