Extremely high-speed cinematography presents its own set of unique challenges. It is an art of its own, that takes much time to understand and master. The applications for extreme high-speed photography are vast. Things that the naked eye perceives as instant and mundane become exciting and visually amazing.
Take a water drop falling into a pool of water for instance. At 1000 fps (around 42 times faster than 24fps, and thus an action that takes one second of real time now takes 42 seconds when played back), we can see the drop of water slowly falling towards the water. When it hits, we can see the water slowly move away from the point of impact, sending a small wall of water upwards. The water rushes back downward and then shoots a drop of water back into the air, straight up.
One of the first questions that should be asked when preparing for a high-speed shoot is if the action you are shooting really needs extreme high-speed camera work. (I consider extreme high-speed to be anything over 150fps.) For example, if the action you are photographing is not that fast to begin with, you most likely do not need camera speeds over 150 fps.
The next thing to consider is how long does the action need to last for? If you are doing a 60-second commercial and the action is 45 seconds long, chances are you will end up needing to cut some of the shot, and thus can justify a lower frame rate. When in doubt, I always recommend shooting at a faster frame rate and then speeding the shot up in post if need be.
Once the above are determined, you can then think about the issue of light. Extreme high-speed photography needs LOTS of light, more than most ever expect. You will find yourself needing to light a small area brighter than sunlight.
Another issue is flicker. All HMI’s, even on a “flicker free” ballast will flicker at a high-frame rate. The flicker takes on several forms, including “arc wander” where you can visually see the ark of the HMI globe moving. All tungsten light sources smaller than 5k will flicker on AC power.
Because of the flicker issue, I usually end up working with large tungsten units, such as 10 and 20k fresnels. The problem is, most of the new high-speed digital cameras are daylight balanced, and thus, you must either use CTB on the lighting units or an 80A filter to get the light balance correct. The tricky thing is, all the color correction sucks up a lot of light.
Lens choice is very important in extreme high-speed shoots because odds are you will need very good close focus abilities and good performance at low T-stops. In most cases you will find yourself shooting between a T2 and T4. Because there is so much light bouncing around, the lenses need to not flare too easily.
Accounting for depth of field is also very important. If you are shooting a macro shot of the lip of a glass at a wide T-stop, keeping the entire glass in focus is not usually possible. If it is important to keep the entire object in focus then more light will be required. A good motto is that you can never have too much light.
With all things film making, scheduling is very important. Many things in extreme high-speed photography are deceptive in the amount of time they will take to photograph. A water drop needs to hit its mark for focus just as an actor must. Getting it perfect takes a long time, and knowing how long these types of actions take to get right just comes with experience (as does the huge bag of tricks that helps speed these types of actions up).
Many producers, upon finding out just how time-consuming this type of photography is, decide farming it out to a company specializing in such things is the most cost effective.
If you do not have experience with this type of work, make sure to consult with people who do. A company specializing in high-speed photography, or the company that is renting you the high-speed camera, may have some good advice for you.
Kevin Zanit is a California-based cinematographer who has worked on numerous commercials and music videos.
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