By Chuck Gloman, June 3, 2008
Capturing the action with a Steadicam-mounted, overcranked HPX500.
Having the Panasonic AG-HPX500 on a shoot is much like your father giving you the keys to his brand new sports car for the weekend. Shooting with this high-definition P2 Ferrari opens up a whole new world to the filmmaker.
DV ran a review of the HPX500 in the September 2007 issue (which can be found here) so I won’t rehash all that this camera does. Instead I’ll focus on one of its unique capabilities that sets it apart from the competition.
While planning a short film opening for our film festival, my students at DeSales University came up with the idea of shooting the project in 720p utilizing the HPX500’s variable-frame-rate capability. In fact, that’s one of the main reasons they selected the Panasonic in the first place.
My students have always shot in 24p because they prefer the “film look” when using our DVX100A cameras. The move up to real high-definition (not HDV) over standard-definition was the easy choice. 720p is actually sharper than shooting in 1080i because you have 720 progressive lines rather than 540 odd and even lines. No matter how bad your math may be, 720 is a bigger number than 540. To make the decision even easier, the HPX500 offers variable frame rates only in the 720p mode, not the 1080i or 480i modes.
You may ask, “Why not just shoot the video normally and change the frame rates in post?” The answer is simple: It actually looks better if you overcrank or undercrank when shooting rather than achieving the effect in editing, as the resulting “jerkiness,” for lack of a better term, is much less obvious if you import the shot at the correct frame rate.
Now that we had determined we would be shooting in 720p/24pN, when should we use the over- or undercranking modes, and which settings would be selected? These answers had to be incorporated into the script, which features two students — Chris and Tim — racing through a building to the control room at the other end. Whoever gets to the switcher first will activate the start of the film festival.
The comedy of the action is more pronounced if the camera is overcranked — shooting more images per second. The result, if the footage is later played back at normal speed (24pN), is that the racing students will be moving in slow motion. Because the normal speed is 24 frames a second (we were shooting natively in 24pN), 48 fps would have been slow and humorous, but a faster 60 fps (slower on the screen) would be even funnier.
With papers floating in slow motion and each student attempting to get into the lead, the slow motion (with the slowed audio) adds to the moment. The actors are still covering the same space in one second, but 60 images are captured and 24 are played back, giving the illusion of slow motion.
Once the boys get into the control room, we changed things up again for comedic effect. Using the undercranking mode and setting the frame rate to 12, the slowest the HPX500 allows, we increased the speed of the action
. Fewer frames are captured of the action resulting in a quickened pace when played back at 24. Playing the image back at 24 fps, Chris and Tim feverishly hunt for the right button on the switcher in a frenzied panic.
Of course, you don’t have to use the variable-speed feature of the HPX500 for comedy. News crews can illustrate the rate of traffic on a highway by undercranking — the end result is still the same, but the faster rate suggests the passage of time. The Panasonic also has a time-lapse feature when a single frame is shot at selected intervals (clouds speeding by, flowers blooming, etc.) Shooting a sporting event in the overcranking mode details how a player performed on the field, with the movement being slow enough to properly analyze.
In order to accurately determine if shooting in a variable-frame rate was the correct creative option for our film fest opener, we did first did some tests. We began by mounting the Panasonic to a Steadicam and shooting the scene in 720p/24pN without adjusting the frame rate. Inserting the P2 card in the P2 player and connecting it to Final Cut Pro, we played both versions (the normal frame rate and the overcranked) to see which one looked best. The footage shot at 24pN, when slowed in FCP, had a blurring effect behind the actors as they moved. To some, this might be the result they are after, but, in my opinion, it looked too jittery and over-processed. (We watched the footage in native HD without downconverting.)
The same footage shot at 60 fps had clearly defined characters in each frame on the timeline. It was as if we could pull a pristine still frame from the timeline without the blurring (and rendering) we saw with the footage we slowed in post. Clearly, the overcranking in the camera looks sharper and cleaner. If you want the blurring effect, then post may still be an option — it would have been our only option if we had used the HPX500 in any other mode than 720p.
We also had a test of the under cranking effect in post as well as shooting it in the camera. Setting the clip’s speed rate to 200 percent, we had the same “look” as shooting the footage in 12 fps. Final Cut did not display any artifacts when increased to double normal speed — so we could have used this effect in post. We ended up using the footage shot at 12 fps because it actually was a better take from the actor’s perspective.
Choosing the correct camera support is also important when using the variable frame rates on the Panasonic. A stabilizing device like the Steadicam made the higher speed footage flow more smoothly, but an inexperienced operator’s footage in the undercranking mode would call attention to every mistake he or she made. Rehearsal is the key for any shoot where the actors know exactly what is expected of them and the crew has their movement honed also. The end result is what the audience may or may not remember, and it our case we hope the fluidity of the over- and undercranking will enhance the audience’s experience.
Cameras keep getting better and better and this small effect would not have been possible a short time ago. My advice has always been to push the technology to its limits and you will be glad you did.
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