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.